Complete Raspberry Pi - 2017

New ¦ Raspberry Pi ¦ Programming ¦ Projects

BDM s

Complete

Raspberry Pi Everything you need to learn to master the Raspberry Pi

194 ES PAG

ials of tips, tutor & projects

Packed with the best tips and tutorials

Easy to understand steps to help you master your Pi

Including coding with the FUZE

Discover amazing Pi projects!

BDM’s Ultimate Series BDM’s

Complete

Raspberry Pi

Everything you need to master the Raspberry Pi The Raspberry Pi has amazed and astounded the world with its diminutive dimensions and powerhouse performance. It’s been used for all sorts of great projects and collaborations and has been utilised in living rooms, nature reserves, the oceans of the world and even in outer space. It really is an incredible little computer. We’ve put together dozens of tutorials, complete with step-by-step pictures, that are easy to follow, to help you get to grips with your Raspberry Pi. We tell you exactly what to do, how to do it and where to go to learn more. There’s plenty here to help you become a Raspberry Pi expert and start your own unique and equally amazing project. There’s never been a better time to learn how to program or how to get the most from electronics and robotics. All you need is your Raspberry Pi, this book and a little imagination and you’re ready to join the millions of other enthusiasts from around the world.

CONTENTS

Contents

Complete Raspberry Pi 6

Raspberry Pi Hardware and Setup

46 Using APT to Install and Remove Programs

8

Say Hello to Raspberry Pi

50 Transfer Files Using FTP

10 Get to Know the Raspberry Pi 12 Up Close with the Raspberry Pi 14 Kit You’ll Need and How to Set it Up 16 Set Up Raspberry Pi Using a Mac 18 Set Up Raspberry Pi Using a Windows PC 20 Set Up Raspberry Pi Using Linux 22 Copying NOOBS Files from Linux

52 Using the Archiver App 54 Using the Task Manager 56 Get More from the Terminal App 58 Using the Leafpad Text Editor 60 Using Libre Office to Create Documents 62 Edit Images with GIMP

Getting to Know Unix

24 Using NOOBS to Set Up Raspberry Pi

64

26 Installing Image Files with Etcher

66 What is Unix?

28 Editing the Config.txt File

68 Understanding Unix

32

Using the Raspbian OS

70 Using the Unix Filesystem 72 Listing and Moving Files

34 Take a Tour of PIXEL

74 Creating and Deleting Files

36 Exploring the Command Line

76 Create and Remove Directories

38 Getting Raspberry Pi Online

78 Copying, Moving and Renaming Files

40 Setting Up a Static IP Address

80 Using the Man Pages

42 Connect Remotely with VNC

82 Editing Text Files

44 Using the Built-in Applications

84 Getting to Know Users

BDM’s: Complete Raspberry Pi

ISBN 978-1-907306-58-7 Published by: . . . . . . . . . . . . Managing Editor: . . . . . . . . . Art Director & Production: Production Manager: . . . . . Design: . . . . . . . . . . . . . . . . . . Editorial: . . . . . . . . . . . . . . . . Sub Editor: . . . . . . . . . . . . . .

Papercut Limited James Gale Mark Ayshford Karl Linstead Robin Drew David Hayward, Russ Ware Paul Beard

Digital distribution by: PocketMags.com For all advertising and promotional opportunities contact: [email protected] Copyright © 2017 Papercut Limited. All rights reserved.

No part of this publication may be reproduced in any form, stored in a retrieval system or integrated into any other publication, database or commercial programs without the express written permission of the publisher. Under no circumstances should this publication and its contents be resold, loaned out or used in any form by way of trade without the publisher’s written permission. While we pride ourselves on the quality of the information we provide, Papercut Limited reserves the right not to be held responsible for any mistakes or inaccuracies found within the text of this publication. Due to the nature of the software industry, the publisher cannot guarantee that all tutorials will work on every version of Raspbian OS. It remains the purchaser’s sole responsibility to determine the suitability of this book and its content for whatever purpose. Images reproduced on the front and back cover are solely for design purposes and are not representative of content. We advise all potential buyers to check listing prior to purchase for confirmation of actual content. All editorial opinion herein is that of the reviewer as an individual and is not representative of the publisher or any of its affiliates. Therefore the publisher holds no responsibility in regard to editorial opinion and content.

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48 Using the File Manager


BDM’s: Complete Raspberry Pi is an independent publication and as such does not necessarily reflect the views or opinions of the producers contained within. This publication is not endorsed or associated in any way with The Linux Foundation, The Raspberry Pi Foundation, ARM Holding, Canonical Ltd, Debian Project, Lenovo, Dell, Hewlett-Packard, Apple and Samsung or any associate or affiliate company. All copyrights, trademarks and registered trademarks for the respective companies are acknowledged. Relevant graphic imagery reproduced with courtesy of Lenovo, Hewlett- Packard, Dell, Samsung, FUZE Technologies Ltd and Apple. Additional images contained within this publication are reproduced under licence from Shutterstock.com. Prices, international availability, ratings, titles and content are subject to change. All information was correct at time of print. Some content may have been previously published in other volumes.

Papercut Limited Registered in England & Wales No: 4308513

Visit us at: www.bdmpublications.com Follow us on Facebook: BDM Publications Follow us on Twitter: @BDMpubs

INTERNATIONAL LICENSING Papercut Limited has many great publications and all are available for licensing worldwide. For more information go to: www.brucesawfordlicensing.com Email:[email protected] Telephone: 0044 7831 567372

CONTENTS

86 Ownership and Permissions

140 Creating Functions in Python

88 Useful System and Disk Commands

142 Conditions and Loops

90 Managing Programs and Processes

144 Python Graphics

92 Input, Output and Pipes 94 How to Customise Unix

96

FUZE and Introduction to Coding

146 Raspberry Pi Projects 148 Create a Music Streaming Box 150 Create a Media Server

98 Introducing the FUZE Project

152 Build a Retro Games Console

100 Setting up the FUZE

154 Raspberry Pi Portable Games Console

102 Getting Started with FUZE BASIC

156 Set Up a Time-lapse Webcam

104 Coding with FUZE BASIC Part 1

158 Build a Web Server


160 Create a Supercomputer

108 Coding with FUZE BASIC Part3

162 Build a CamJam EduKit Robot

110 Using a Breadboard

164 Controlling Your Robot

112 Using the FUZE IO Board

166 Add Sensors to Your Robot

114 Using a Robot Arm with FUZE BASIC

168 Turn an RC Toy into a Robot

116 FUZE BASIC Examples 1

170 Using GitHub

118 FUZE BASIC Examples 2 120 Introducing Scratch

172 Raspberry Pi Add-ons and Extras

122 Getting Started with Scratch

174 The Best HATs for Your Raspberry Pi

124 Creating Scripts in Scratch

180 Raspberry Pi Kits

126 Interaction in Scratch

182 Raspberry Pi Cases

128 Using Sprites in Scratch

184 Raspberry Pi Robots

130 Sensing and Broadcast

186 Raspberry Pi Screens and Displays

132 Creating and Using Variables

188 Android Apps for Pi Users

134 Getting to Know Python

190 Essential Software

136 Start Using Python

192 Common Raspberry Pi Problems

138 Working with Variables

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Raspberry Pi Hardware and Setup INDEX

Raspberry Pi Hardware and Setup Using the Raspberry Pi should always start with understanding the hardware. There are several versions of the Raspberry Pi available: Pi 1 Model A+, Pi 1 Model B+, Pi 2 Model B, Pi 3 and Pi Zero. Confused? You needn’t be. The Raspberry Pi may be diminutive in size but it’s a surprisingly powerful computer. This little powerhouse is capable of so much but first we need to make sure we have everything needed to get up and running. Throughout this section we help you figure out what’s needed in terms of connectivity, the extra hardware and of course the operating system itself. From there we look at getting the Raspberry Pi set up and ready to use, regardless of whether you’re working with a Windows PC or Apple Mac. By the end of this section you’ll have a Raspberry Pi running the latest version of Raspbian (the official RPi operating system) and brimming with potential.

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20 Set Up Raspberry Pi Using Linux

10 Get to Know the Raspberry Pi

22 Copying NOOBS Files from Linux

12 Up Close with the Raspberry Pi

24 Using NOOBS to Set Up Raspberry Pi

14 Kit You’ll Need and How to Set it Up

26 Installing Image Files with Etcher

16 Set Up Raspberry Pi Using a Mac

28 Editing the Config.txt File

18 Set Up Raspberry Pi Using a Windows PC



7



Let’s take a look at the best-selling British computer ever: the Raspberry Pi! This bare-bones machine just looks like any other piece of circuitry, until you realise it’s a full-blown credit-card sized computer ideal for learning programming and home hacking.

The Raspberry Pi is a British built low cost computer that enables everybody to learn computing, start programming and explore basic electronics. It’s the size of a credit card but capable of running a full operating system and doing everything a desktop does. More importantly, with the Raspberry Pi you install your own operating system, connect all your devices and create your own programs using languages like Scratch and Python. There’s no case so you can hook up electronic circuits to the pins and control them to get input and output, so you can hack together electronic projects at home. Setting up a Raspberry Pi is pretty simple, and throughout this book we’ll take you step-by-step from unboxing your Raspberry Pi to setting it up and getting started. There are many different models of Raspberry Pi available and each has slightly different features (see opposite). The fundamentals of each Raspberry Pi are similar though. Each model is a lightweight computer on a single board that’s roughly the size of a credit card. Each Raspberry Pi board features a processor made by ARM, which is similar to the models you find in a mobile phone. The ARM processor is fast and lightweight but it runs a different set of software than you might be used to. There are many different operating systems (OS) available, but for most of this book we’ll focus on one called Raspbian JESSIE with PIXEL, which is the OS recommended by the Raspberry Pi Foundation.

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There’s no hard drive on the Raspberry Pi, instead the operating system is installed on an SD Card (the cards typically used in cameras). The operating system is installed onto the SD Card by copying the files to the SD Card using a computer. We’ll show you how to set up Raspbian JESSIE with PIXEL (and other OS’s) using a Mac, Windows or Linux computer. Once you have an OS installed on the SD Card you can set up your Raspberry Pi. The Raspberry Pi is connected to a monitor via a HDMI socket whilst a keyboard and mouse is attached to the USB socket. A smaller Micro USB connection is used to provide power to the device. Most Raspberry Pi models feature an Ethernet connection, and an Ethernet cable is connected from your Raspberry Pi to a socket on your modem router. The Raspberry Pi 3 has built in wireless networking and Bluetooth, making it easy to get online. You can attach a USB Wi-Fi dongle or Ethernet adaptor to older models. First it will help to know which Raspberry Pi you are using. This can be tricky as there have been several distinct models so far. The layouts opposite will help you determine which Raspberry Pi you have. This book covers all the different models, and they offer largely similar features, although newer models offer additional extras. Once you know which Raspberry Pi you own, you can get it up and running.


Raspberry Pi 3

Raspberry Pi 2 Model B Raspberry Pi 1 Model B+

The Raspberry Pi 3 is the main model on sale today. It packs a super-fast 1.2GHz 64-bit quad-core CPU and 1GB of RAM. This is faster than many modern smartphones and puts it firmly on a par with many desktop computers. The Raspberry Pi 3 isn’t just faster; it’s also more feature-rich. It now has wireless networking and Bluetooth built it. This makes it much easier to get online and use a wireless keyboard and mouse. It also comes with Ethernet and four USB sockets. So it’s easy to connect it to your network router and hook up any wired devices. Like all models it features the full 40-pin GPIO sockets. It’s easy to attach hardware and experiment with electronics using a Raspberry Pi 3. It’s slightly more expensive than other models and you can usually pick a board up for around £30. It’s well worth the extra money though and is the board we recommend most newcomers buy.

Raspberry Pi 1 Model A+

The older Raspberry Pi 2 model still found on sale. It has the same form factor as the Raspberry Pi 3 with 4 USB Ports, Ethernet connection and Micro USB. It may look the same but it has a slower 900 MHZ quad-core ARM Cortex-A7 CPU and 1GB RAM. This brings it close in line to many low-end desktop computers. Complicating matters slightly is the existence of a Raspberry Pi Model 1 B+, which is identical in layout to the Raspberry Pi Model 2 but with an even slower ARMv6 700MHz processor. If you are confused which type you own then type cat /proc/cpuinfo at the command line. If it lists four ARMv7 processors you are using a Raspberry Pi 2, if you see just one with ARMv6 then you have the older Raspberry Pi Model 1 B+.

Raspberry Pi Zero

It’s worth knowing that unlike desktop computing, it isn’t always the case that you need or want the most powerful Raspberry Pi available. Projects that require very low power consumption, and that aren’t dependent on Ethernet or USB work best with the Model A+, as it uses between 0.5W and 1W to operate. However, the newer Model A+ has many features also found on the more recent models. In particular it has 40 GPIO pins; the first 26 pins are in the same layout as the Model A and B. It also replaces the older SD Card socket with the neater Micro SD variant. Unlike the Raspberry Pi 3, it has just a single USB port and no built-in Ethernet connection. It uses a smaller form factor with the GPIO pins on one side. You don’t need to solder them in though. It’s a good compromise between the Raspberry Pi 3 and Pi Zero. You can usually pick one up for around £20. If you’re a newcomer it’s a better idea to buy the Raspberry Pi 3 instead and get the extra ports and wireless networking.


The new Raspberry Pi Zero is a super small, super cheap computer that costs just £4. It’s half the size of the model A+ but has a surprising amount of power, including a 1Ghz single-core CPU and 512MB RAM. It has the full 40-pin GPIO header but you’ll need to buy the pins separately and solder them in. It uses the same Micro-SD card as the other Raspberry Pi devices, so you can swap SD cards between them. Last but not least, it draws an incredibly low amount of power (Micro USB) making it id eal for small power devices. The ports are smaller than you’d find on the larger Raspberry Pi though, so you’ll need a mini-HDMI adaptor as well as a micro-USB adaptor to connect devices. A four-port USB Hub and Ethernet adaptor will come in handy too.


9


Get to Know the Raspberry Pi The Raspberry Pi is a marvellous microcomputer used to learn coding and for hacking home projects. It’s small, cheap and easy to get started with; here’s what you need to know about the Raspberry Pi. 40 GPIO Pins The GPIO (General Purpose Input Output) pins can be accessed directly on the Raspberry Pi. These are used in projects to connect the Raspberry Pi to electronic circuits and control electric devices. Some can be turned on and off while the Raspberry Pi is running.

ARM-Powered At the heart of the Raspberry Pi 3 is a Broadcom BCM2837 System on Chip (SoC). It contains a powerful 1.2GHz 64-bit quad-core ARM Cortex-A53 CPU. This is 50-60 percent faster than the Raspberry Pi 2 and ten times as fast as the original Raspberry Pi.

DSI The Display Interface (DSI) can be used to connect a display directly to the Raspberry Pi board.

SD Card Slot

USB Power

Instead of a hard drive you use an SD Card with the Raspberry Pi. The Raspberry Pi 3 (pictured here) uses a Micro SD Card. Some older Raspberry Pi models use a regular SD Card.

A standard Micro USB power supply is used to provide power to the Raspberry Pi. You don’t get a power supply but can use any 5V 2000mA Micro USB power supply and compatible cable, or buy an official power supply separately.

10


Get to Know the Raspberry Pi

USB ports The Raspberry Pi USB Ports to connect standard computing accessories such as a keyboard, mouse and webcam. Raspberry Pi 2 and 3 boards contain four USB ports but you might need a USB Hub to get more ports on the Raspberry Pi A+ and Pi Zero.

Ethernet and Wi-Fi Connect the Raspberry Pi 3 to a network or home modem router using an Ethernet cable and this connection. The Raspberry Pi 3 has built in wireless networking, but you must add a USB Wi-Fi adaptor to older models.

3.5mm Audio/Video jack This 3.5mm audio jack is normally used to attach headphones or speakers. On the Raspberry Pi 2 and 3 it also carries composite video using a compatible cable.

CSI (Camera Serial Interface) You can attach the official Raspberry Pi Camera Module directly to the motherboard via this CSI connection.

HDMI The HDMI connection enables you to hook up the Raspberry Pi to most modern monitors and digital televisions. It carries both video and audio.



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Up Close with the Raspberry Pi 3 The Raspberry Pi 3 takes everything that made the Raspberry Pi such a roaring success and made it a little bit better. Let’s see what features are on the latest Raspberry Pi board. FASTER AND CONNECTED

The new Raspberry Pi board has a faster processor, making it more like a regular desktop computer. It also packs better connectivity features.

STEP 1

If you’re familiar with the Raspberry Pi, you’ll notice that the Raspberry Pi looks a lot like the Raspberry Pi 2. It has the same board, with the components laid out in the same place. This design is handy because all the hardware designed for the Raspberry Pi 2 will work with the new board.

STEP 2

Faster CPU. The marquee feature for the Raspberry Pi 3 is a new BCM2837 System on Chip (SoC). This system contains a custom hardened 1.2GHz 64-bit quad-core ARM Cortex-A53 CPU to the Raspberry Pi, which is 50-60 percent faster than the Raspberry Pi 2 and ten times as fast as the original Raspberry Pi.

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STEP 3

The next cool addition to the board is a BCM43438 wireless combo chip; which gives the Raspberry Pi built-in Wi-Fi and Bluetooth 4.1. In many ways this is cooler than the faster CPU, because it will make it much easier to create Internet of Things (IoT) devices.

STEP 4

The 40 GPIO (General, Purpose Input Output) pins remain the same as before. This is vital because it would be confusing to have a new GPIO layout, and popular hardware attachments like HATs (Hardware Attached on Top) wouldn’t work.

Up Close with the Raspberry Pi 3

Raspbian. Alongside the new Raspberry Pi 3 comes a new version of Raspbian (the operating system). The February 2016 version of Raspbian Jessie comes installed with Python, Scratch, Sonic Pi, Java, Mathematica, so it’s a great system for learning coding and development.

STEP 5

All of the connectors are in the same place, so the board has the same functionality as previous Raspberry Pis. You can use it to build the same electronics projects, and follow the same projects like the Raspberry Pi 2. You just won’t have to attach Wi-Fi or Bluetooth dongles as these are now included.

STEP 6

CONNECTIONS AND SETUP

Setting up the Raspberry Pi 3 is the same process as the Raspberry Pi 2 but there are a few things to keep in mind. It has the same connections but some of them work slightly differently. Here are some things to bear in mind. The Raspberry Pi 3 has four USB ports, and because you no longer need Wi-Fi and Bluetooth dongles, you’ll be even less likely to need more. However, because the Wi-Fi and Bluetooth are onboard, you will need to be careful to provide enough power.

The SD Card slot no longer features the push-to-eject function, you now have to pull the SD Card out (as you do on the Raspberry Pi 1 and Pi Zero). This isn’t a problem, although you might find it harder to eject the SD Card if you’re using a case.

The Raspberry Pi 3 board can still be run from a 5V micro-USB power adapter. This time round, Raspberry Pi recommends a 2.5A adapter if you want to connect USB devices to the Raspberry Pi. This will ensure they get enough power to work correctly.

The Raspberry Pi 3 still fits inside the official case, which is a great idea if you’re looking to work on projects. It protects the board from the elements and you can quickly take it apart to access GPIO pins and other internal components.

STEP 1

STEP 2


STEP 3

STEP 4


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Kit You’ll Need and How to Set it Up The Raspberry Pi is as bare bones as a computer can get. You get a motherboard, but not much else. So you’ll need a few extras to get it up and running but they’re things you’re likely to have or at least find it easy to get your hands on. ASK AROUND

The kit list required to set up a Raspberry Pi is pretty basic: keyboard, mouse, HDMI monitor, SD Card and an optional case. Many of these items you’ll already have, but don’t rush out and buy those you don’t. Ask around to see if anybody you know has spares.

STEP 1

The most important thing you need is an SD Card. These are the storage cards commonly found in digital cameras. All modern Raspberry Pi boards, including the Raspberry Pi 3 and Pi Zero, use Micro SD cards but the older boards may use a larger SD Card.

You’ll need a HDMI cable to connect your Raspberry Pi to a monitor or television set; these cables are used with modern televisions and video game consoles, so you shouldn’t find it too hard to pick up a spare. If you own a Pi Zero you’ll also need a Mini-HDMI to HDMI adapter as this is generally the best way forward.

The SD Card plugs into the SD Card socket. On the Raspberry Pi 3 and Pi Zero you push the card in and pull it out. On some older models you push the SD Card in again to eject it. All SD Cards have a notch on one corner that ensures it only goes in one way round. Unless you bought a card with NOOBS preinstalled, you’ll need to install the software on it first.

You’ll want to connect your Raspberry Pi to the Internet. The Raspberry Pi 3 has built in wireless networking and Ethernet. The Model A+ and Raspberry Pi 2 include an Ethernet socket but the Pi Zero and older boards will require either an Ethernet adaptor or a Wi-Fi dongle to get online.

STEP 2

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STEP 3

STEP 4

Kit You’ll Need and How to Set it Up

The Raspberry Pi 3 comes with four USB sockets but if you own a Pi Zero you may need to purchase a USB Hub. These connect into the USB socket, and provide four (or more) USB connections. You typically need to connect a keyboard and a mouse so at least two USB ports are required. Speaking of which…

STEP 5

GETTING EVERYTHING CONNECTED

Now that you’ve got all the basics you’ll need to get everything set up. If you haven’t installed the NOOBS files on your SD Card, then it’s best to do that first (see the next few pages). Connect your Raspberry Pi to the monitor using the HDMI cable. Now attach the keyboard and mouse to separate USB ports. If your Raspberry Pi only has one USB port, connect the mouse and keyboard to the USB hub and attach it.

STEP 1

Now, if required, connect the Ethernet cable to the Raspberry Pi. Connect the other end of the cable directly into your modem/router or into a network socket.

STEP 2

Two things that should be easy to find are a USB Keyboard and USB Mouse. We generally prefer USB devices that plug directly into the Raspberry Pi, but devices with wireless dongles generally work just as well. Only the Raspberry Pi 3 comes with Bluetooth as standard, so avoid Bluetooth mice and keyboards.

STEP 6

Finally connect a Micro USB cable to the power supply and attach the other end to a 5V USB power adapter. This is the type used to power most modern smartphones, so you should be able to source a spare. Press the On button to power up your Raspberry Pi.

STEP 3

You can also choose to house your Raspberry Pi in one of many enclosures like the official one pictured here.

Consider a case to hold your Raspberry Pi together. Raspberry now makes an official case that you can use to hold all the components and protect it from knocks and drops.

STEP 4



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Set Up Raspberry Pi Using a Mac You should install NOOBS (New Out Of Box) starter software on your SD Card before you go any further. This feature looks at how to format an SD Card and copy the software using an Apple Mac computer. GETTING TO KNOW NOOBS

The easiest way to get up and running is to use NOOBS, a software program created by the Raspberry Pi Foundation. You can buy a NOOBS SD Card from Raspberry Pi but it’s easy to make your own with an old unused SD Card (8GB recommended).

STEP 1

You’re going to use a utility called SD Card Formatter 4 to erase the SD Card with correct formatting. You can download this app from https://www.sdcard.org/downloads/formatter_4/. Click Download SD Formatter for Mac and Accept. Click the SDFormatter.pkg file in your Downloads folder and follow the instructions to install the app.

STEP 2

You’re going to use a 8GB SD Card to install the operating system on our Raspberry Pi. The card needs to be formatted, which will erase all the data on it, so make sure you have copied any files from it you want to save. Insert the SD Card into your Mac, either directly into the SD Card slot or with an SD Card adaptor.

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STEP 3

Make sure the card is present in the Select Card area; you should only have one SD Card inserted into your Mac. Open SDFormatter and choose the Overwrite Format option to ensure that all the old data is removed from the card. Enter a name for the card in the Name field to help you identify it; although this isn’t necessary for the installation process.

STEP 4

Click the Format button when you are ready to wipe the card. There are other ways to format SD Cards in macOS (in particular Disk Utility) but the advantage of SD Card formatter is that it wipes SD Cards with the correct FAT32 format and doesn’t affect the protected partition. It can take a while to format the SD Card, but the progress bar will show you how the process is going.

Set Up Raspberry Pi Using a Mac

When SD Card formatter has finished formatting the SD Card it will be mounted so you can access it. By default mounted volumes appear as an icon on the desktop. If not open a new Finder window and check for it under Devices. Check that the SD Card is accessible and click Close in SDFormatter.

STEP 5

Now it’s time to download the NOOBS software from the Raspberry Pi website. Open Safari and enter www. raspberrypi.org/downloads/ into the Smart Search Field. Scroll down to find the NOOBS section (not NOOBS LITE) and click Download Zip. A zip file containing the NOOBS files will be placed in your Downloads folder.

STEP 6

COPY THE SOFTWARE

Transfer the NOOBS files to your SD Card to continue the setup process. Open the downloads folder and click on the NOOBS zip file to unzip it. A NOOBS folder should appear in your downloads; it will be marked with the version number. Ours is called “NOOBS_v1_9_3”. Click on the folder to open it and view all the files contained inside.

STEP 1

Press Command-A to select all the files inside the NOOBS folder. Now drag and drop all the files from the NOOBS folder to the SD Card. This will copy all of these files to the root (the base) of the SD Card. Make sure you copy the files, not the NOOBS_v1_9_3 folder containing them.

STEP 2


Wait for all of the files to be copied from your Downloads folder to the SD Card. After the files have finished copying open the SD Card and check that all of the files are in the root. You should see “bootcode.bin” and “BUILD-DATA” files, and a “defaults” folder among other files.

STEP 3

Make sure you eject the SD Card properly. Do not just remove it from the Mac. Instead, drag the SD Card icon to the Trash to eject it from your system. Or open a new Finder window and locate the SD Card under Devices, click the small Eject icon next to it. Now remove the SD Card from your Mac. It is ready to be inserted into your Raspberry Pi.

STEP 4


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Set Up Raspberry Pi Using a Windows PC It’s easy to set up your Raspberry Pi with a Windows PC by downloading and copying NOOBS software. This installs a selection of OS’s onto the Raspberry Pi. Format your SD Card and install NOOBS using a Windows PC. SETTING UP WITH NOOBS

NOOBS (New Out Of Box Software) is a program used to make setting up a Raspberry Pi simple. You can buy SD Cards with NOOBS preinstalled, but here we’ll look at how to format your SD Card and install NOOBS using a Windows computer.

STEP 1

You’re going to use a utility called SD Card Formatter 4 to erase the SD Card with correct formatting. You can download this app from https://www.sdcard.org/downloads/formatter_4/. Click Download SD Formatter for Windows and click Accept and Open. Double-click Setup and choose Run then follow the Install instructions.

STEP 2

You’re going to use a 8GB SD Card to install the operating system on our Raspberry Pi. The card needs to be formatted which will erase all the data on it, so make sure you have copied any files from it you want to save. Insert the SD Card into your PC, either directly into the SD Card slot or using an SD Card adaptor. Open the SDFormatter program.

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STEP 3

The Drive area should be set to F. Click Refresh if it can’t find your SD Card. Click Option and change Format Type to “Full (Erase)” and click OK. Enter a name in the Volume Label field to make it easier to identify the card (we used “SD Card”).

STEP 4

Click the Format button and OK when you are ready to wipe the card. There are other ways to format SD Cards in Windows but the advantage of SD Card formatter is that it wipes SD Cards with the correct FAT32 format and doesn’t affect the protected partition. Click OK again when the format is complete.

Set Up Raspberry Pi Using a Windows PC

Click Exit to close down the SDFormatter program. Click Start > File Explorer and choose the SD Card in the sidebar. The drive should be empty but we will copy the files to it in the next steps. For now just make sure that you can access the empty root of the SD Card.

STEP 5

Now it’s time to download the NOOBS software from the Raspberry Pi website. Open a web browser and enter www. raspberrypi.org/downloads/ into the URL field. Scroll down to find the NOOBS section (not NOOBS LITE) and click Download Zip and Save. A zip file containing the NOOBS files is copied to your Downloads folder. Click Open Folder when it is done.

STEP 6

COPY THE SOFTWARE

Continue making your SD card by copying the files across.

STEP 1

A NOOBS folder should appear in your downloads (it will be marked with the version number, ours is called “NOOBS_v1_9_3”. Double-click the NOOBS zip file in your Downloads folder to view the contents. These are the files you need to copy to the root (base) of your SD Card.

Wait for all of the files to be copied from your Downloads folder to the SD Card. The files that are copied will install an operating system of your choice on the Raspberry Pi when you first boot it up. It is important that the files are copied to the root (base) of the SD Card and are not inside another folder such as the NOOBS folder.

Click Extract All to expand the zipped file and extract its contents. Click Browse in the Select a Destination and Extract Files folder and choose “SD Card(F:)” in the Select a Destination window. Click Select Folder and Extract. The files will now be copied directly from the zip file to your SD Card.

Click Start > File Explorer and choose “SD CARD (F:)” in the sidebar to display the contents. It should now contain all the files NOOBS needs to setup an operating system on your Raspberry Pi. Check that you can see a Defaults folder, bootcode and BUILD-DATA files along with the other files shown here. Remove the SD Card from your Windows PC. It’s now ready to be inserted into the Raspberry Pi.

STEP 2


STEP 3

STEP 4


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Set Up Raspberry Pi Using Linux In some ways using Linux is the best start for Raspberry Pi computing, as most Raspberry Pi OS’s are based on Linux. Formatting an SD Card in Linux is a more detailed process but you get a better understanding of what is happening. PARTITIONING AN SD CARD

In this feature we’ll format an SD Card using the Terminal in Ubuntu Linux. Formatting an SD Card in this manner is a detailed process but learning to format a card using command line instructions will stand you in good stead for using a Raspberry Pi.

STEP 1

The SD Card needs to be formatted using the FAT32 format. The best way to do this in Linux is to use the fdisk command in a Terminal window. Open Terminal in Ubuntu by clicking Search and entering Terminal; alternatively press Command-Alt-T to open a Terminal window.

STEP 2

You’ll need sudo (or root) access to format the memory card. Check that you have sudo privileges by typing sudo -v in the command line. You will be prompted for your account password, type it and press Return. If you see “Sorry, user may not run sudo on ubuntu” then you need to switch to an account with Administrator access.

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STEP 3

You need to find discover which device the SD Card is listed as. Make sure the SD Card is not connected and enter sudo fdisk -l to list all the Devices. Now attach the SD Card, ignore the window that appears and enter sudo fdisk -l again. This will show you which device you have.

STEP 4

In our test I get /dev/sda and /dev/sdb in the first run as my computer has two hard drives. Running fdisk with the SC Card inserted results in /dev/sda, dev/sdb and dev/sdc. Checking further I see that dev/sdc has 7948MB which matches my SD Card. So that’s the one I need to format.

Set Up Raspberry Pi Using Linux

Now that you know which drive is your SD Card, it’s time to start the formatting process. Be aware that this will remove all the data from the card, so make sure you copy anything you want to save. Enter sudo fdisk /dev/sdc (replacing sdc in your code with the name of the SD Card device you found in the previous step.

STEP 5

You should see “Command (m for help):”. Enter m and press Return to view the command actions available in fdisk. We are going to use the d command action to delete the partitions currently on the SD Card, then the n command to create a new partition and p to print out and test the partition.

STEP 6

FORMATTING THE PARTITION

Format your SD Card’s partition to prepare it for the install files. Enter d and press Return. If you are asked for the Partition number, enter 1 and press Return. Now enter p and press Return to see if there are any other partitions. Enter d and the number of any partitions until they’re all gone. Enter p and Return one final time to ensure that you have no partitions left.

Enter p one final time to ensure that you have a single partition on your SD Card. We now need to change its System type from Linux to FAT32. You can enter L to view all the codes available, but W95 FAT32 is listed as b. Enter t and b and press Return. Terminal displays: “Changed system type of partition 1 to b (FAT32)”. The partition step is to enter w and press Return; this writes the changes to the SD Card.

You need a partition on our SD Card to install NOOBS on. While still in fdisk enter n and press Return. You will be asked to confirm the partition type, two options are available primary and extended. Enter p and press Return. It will ask you for the Partition number, enter 1 and press Return. It will ask you for the First sector and Last sector, press Return twice to choose the default settings.

So far we have created a partition but we haven’t actually formatted it. To do this we have to format the partition (number “1”) and not the whole SD Card. Enter sudo mkfs.vfat /dev/ sdc1. (replacing “sdc1” with the name of your partition, such as “scb1”). You’re done with partitioning and formatting our SD Card, in the next tutorial we’ll look at how to download and install the NOOBS software to the SD Card.

STEP 1

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STEP 3

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Copying NOOBS Files from Linux Once you have formatted the SD card in Linux, you’ll need to download the NOOBS set up files and copy them to the SD card. This is slightly more complex than using Windows or macOS, but once you’ve copied the files over, you’ll be able to set up your Raspberry Pi. USING NOOBS

In this feature we will download the NOOBS (New out Of Box) software from the Raspberry Pi website. This software is then copied to the SD Card, which is inserted into a Raspberry Pi. NOOBS enables you to choose which OS you want to use when you first start the Raspberry Pi.

STEP 1

You can download the latest version of NOOBS from the Raspberry Pi website. Open a web browser and enter www. raspberrypi.org/downloads into the URL field. Click Download ZIP and choose Save File and click OK. The file will be saved to your Downloads folder.

STEP 2

You’re going to extract the files from the NOOBS zip file directly to the SD Card. Remove and insert the SD Card to make sure it is mounted, so you can access the volume. A window should appear on the desktop displaying the contents of the SD Card, which should be empty. Close the window.

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STEP 3

Open the Files application and click Downloads, underneath Places, to view the NOOBS zip file (our version is NOOBS_ v1_9_3.zip). Double click the zip file to open it in the Archive Manager application. You should see two folders “defaults” and “os” and a set of files. You copy these files to the SD Card, not the zip file containing them.

STEP 4

You’re going to extract the files directly to the SD Card to make sure that you copy all the files and not the container. Click Extract to open the Extract window. Now choose the SD Card from underneath Devices. Ensure that Keep directory structure is selected and click the Extract button.

Copying NOOBS Files from Linux

The files will be extracted from the zip file to the SD Card. This process may take a bit of time as it’s a large file and SD Cards copy slower than other drives, so make a cup of tea while you want. When the process is finished an alert window will appear with “Extraction completed successfully”, so click the Close button.

STEP 5

The SD Card now contains a fresh NOOBS installation and can be used to install a range of different operating systems on the Raspberry Pi. Click Quit on the Extraction Completed Successfully alert. Click on the SD Card in Files and check that the files have been copied. It should look like this. Remove the SD Card and place it in your Raspberry Pi.

STEP 6

COMMAND LINE INSTALLATION

Here’s how to install NOOBS directly from the command line. Command line hackers may prefer to install NOOBS from Terminal instead of using the desktop interface. This is possible, and a neat trick to learn. Open a Terminal window (CommandShift-T) and enter cd ~/Downloads then wget “ http://downloads. raspberrypi.org/NOOBS_latest”. This downloads the latest version of NOOBS to your Downloads folder.

You need to find the location where the SD Card is mounted. Enter sudo fdisk -l to check the Disk location (ours is / dev/sdc). Now enter mount | grep -i sdc. You should see something like “/dev/sdbc on /media/lucy/6EFC-286B”. The second directory here is the folder you need to switch to. Enter cd /media/lucy/6EFC-286B, replacing the directory with your own.

Ensure that the file you have downloaded is all present and correct by using its checksum. Enter sha1sum NOOBS_ latest and check that the digits are the same as the ones next to SHA-1 listed at www.raspberrypi.org/downloads/. Pull out and reinsert the SD Card to make sure it is mounted.

Finally you need to extract the NOOBS_latest file in our Downloads folder to the current directory. Enter unzip ~/ Downloads/NOOBS_latest and the files will be extracted directly to your SD Card. Remove the SD Card and insert it into your Raspberry Pi to continue the installation.

STEP 1

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STEP 3

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Using NOOBS to Set Up Raspberry Pi Once you’ve copied the NOOBS files to your SD card using either macOS, Windows or Linux, then you’re ready to install Raspbian OS onto your Raspberry Pi. You’ll then be able to use your Raspberry Pi as a computer. These steps show you just how easy it is to get started. SET UP YOUR OPERATING SYSTEM

NOOBS (New Out Of Box Software) is the standard way to set up an operating system and start using your Raspberry Pi. In previous tutorials we’ve shown you how to install NOOBS onto an SD Card; now it’s time to use NOOBS to set up your Raspberry Pi.

STEP 1

Insert the SD Card containing NOOBS software into your Raspberry Pi and connect the cables, including the HDMI cable and a keyboard and mouse. Finally insert the Micros USB cable connected to the power adaptor to start up the Raspberry Pi. You should be greeted with this screen.

STEP 2

A whole bunch of different operating systems are available but you need to have your Raspberry Pi connected to a network to download them. For now place a tick next to Raspbian [RECCOMENDED]. Check that the Language and Keyboard options at the bottom are correct: most likely you will want English UK and GB. Click the Install icon.

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STEP 3

The NOOBS SD Card will now extract the Raspbian files to the SD Card so that when you next boot up you will run the Raspbian operating system. There’s not much you can do during the installation process but read the various tips and hints that appear during installation. Installation typically takes around 20 minutes so now’s a good time for a break. When it’s finished you will see OS’s Installed Successfully. Click OK.

STEP 4

The Raspberry Pi will now boot directly into Raspbian with PIXEL, the name of its new interface. The interface should be familiar to anybody who has used either a Mac or Windows computer. There is an Applications Menu in the top left that is used to open programs.

Using NOOBS to Set Up Raspberry Pi

Your Raspberry Pi is now ready to use. Click on the Applications folder to view a list of all the programs available. There is a range of Programming tools, Office apps and Internet tools.

STEP 5

It’s a good idea to change the default password, which is ‘raspberry’. Choose Applications > Preferences > Raspberry Pi Configuration and click Change Password. Fill out the “Enter new password” and “Confirm new password” fields and click OK and OK again.

STEP 6

INTERNATIONAL OPTIONS

Ensure that your Raspberry Pi works in your locale. Choose Applications > Preferences > Raspberry Pi Configuration and click Localisation. Four options are available: Set Locale, Set Timezone, Set Keyboard and Set Wi-Fi country. By default the Raspberry Pi is set up for the UK, and you may want to adjust these options if you are in another territory.

If you have a Raspberry Pi Camera Module you should use the Enable Camera option. Click Interfaces and set Camera to Enabled. The SSH option is enabled by default, and it’s a good idea to leave it on. We’ll look at VNC in later chapters but it’s worth remembering you can Enable it here. Click OK.

If you are in America, it’s best to set the Locale to en (English) and the Country to US (USA) with UTF-8 as the Character set. Click OK. Now click Set Keyboard and choose United States as the Country and English (US) as the keyboard; or choose the language and keyboard options that you prefer. Click OK to use your Raspberry Pi.

Return to the System tab to check out a few other options. By default the Raspbian operating system starts up in the PIXEL desktop. Advanced users may prefer to boot To CLI (command line). We suggest leaving it at To Desktop for now. Click OK. The “Reboot needed” alert appears. Click Yes to restart the Raspberry Pi with the new settings.

STEP 1

STEP 2


STEP 3

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Installing Image Files with Etcher Many operating systems, including Raspbian with PIXEL, can be downloaded as image files. These are copied bit-for-bit from the downloaded file to the Micro SD card. Copying image files can be complex but Etcher is an app that makes copying image files a lot easier to do. SET UP ETCHER

Installing with NOOBs is fine but as you become more familiar with the Raspberry Pi you’ll want to install from image files.

STEP 1

First install the Etcher app. Open etcher.io in the web browser and click the Download for Windows, Download for Mac or Download for Linux button depending on your system. The installation file will be saved to your Downloads folder.

STEP 2

Wait for the installation file to finish downloading and open the Downloads folder. Double-click the “Etcher-win32-x64” setup application and follow the installation instructions. If you’re on a Mac, drag the Etcher file to the Applications folder and double-click it to open the program.

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STEP 3

Return to your web browser and download the Raspbian Jessie with PIXEL image from the Raspberry Pi website (raspberrypi.org/downloads). Click Download ZIP under Raspbian Jessie with PIXEL. The image file will also be saved to your Downloads folder.

STEP 4

You should unzip the compressed file to get the image file inside. Open the Downloads folder in Windows, right-click on the file 2016-05-27-raspbian-jessie file and choose Extract All. Click Extract.

Installing Image Files with Etcher

When Etcher opens you’ll see three steps: Select Image, Select Drive and Flash! (“Flash” is another way of saying copy). You’ll look at flashing the Micro SD card in the following steps but first you should take a look in Settings.

STEP 5

Click the Settings cog in the top right of the Etcher window. The first three options are all selected by default and the Advanced option below, marked “Unsafe mode: dangerous” should be deselected. Make sure there isn’t a tick next to Unsafe Mode. Click Back and then you can start flashing your Micro SD card.

STEP 6

IMAGE FILES

Image files contain an entire drive in a single file (ending in .img). The image file can be anything but you’ll usually copy a whole operating system, like Raspbian Jessie with PIXEL. This is copied bit for bit from the file to the Micro SD card so you can start your Raspberry Pi. Click Select Image in Etcher. Select the Downloads folder in the Explorer/Finder window and locate the 2016-05-27-raspbian-jessie image file. Be sure to pick the image file and not the zip file. Click Open.

As you attach the Micro SD card the Etcher section marked: “Select Drive 2” will display the card. Typically it will say D (or E): and 8.0GB. Click Change to view all the drives available but it will only show SD Cards attached, so you should only have one to choose from.

Now attach a Micro SD card to your computer, typically using the Micro SD Card to USB adaptor. The Micro SD card will need to be at least 8GB in size to hold Raspbian Jessie with PIXEL. The card will be completely formatted by Etcher, so be sure you don’t have any important files on the card.

Click Flash to start copying the image file to the Micro SD card. The card will be completely formatted and the the image file will be copied to the card and finally verified. When the process has finished, remove the Micro SD card and insert it into your Raspberry Pi.

STEP 1

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STEP 3

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Editing the Config.txt File Unlike in a normal computer, the Raspberry Pi doesn’t feature a BIOS system to control the initial boot parameters. Instead, it uses a simple configuration file that, when stored in the boot partition of your Micro SD card, can act in a similar way to a BIOS. Depending on the type of project you are planning, being able to control the boot parameters of your Pi device could be a very useful option.

ACCESSING THE CONFIG.TXT FILE This file is normally accessible as /boot/config.txt from Linux and must be edited as root but from Windows or macOS, it is seen as a file in the only accessible part of the card (once you insert the card into your computer). If you need to apply some of the configuration settings shown here but you don’t have a config.txt on your boot partition yet, then simply create it as a new text file. Any changes you make to the file will be applied after you reboot your Raspberry Pi.

Two examples are: # hdmi_mode=4 # disable_overscan=0 Viewing Current Settings in Linux You can view the currently active settings that the config.txt file is controlling via Linux, with just a few simple commands.

Display a specific config value = When editing or creating your config.txt file it is important to follow vcgencmd get_config the simple text format. The format is a single property=value entry Display all integer config options set = on each line, where value is either a string or integer. In the newer Raspberry Pi models there is # before every line. If you want changes vcgencmd get_config int to have an affect then ‘uncomment’ meaning remove the #. Display all string config options set = vcgencmd get_config str

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Editing the Config.txt File

CONFIG.TXT OPTIONS

Here we have a selection of some of the most useful config options you can edit. We have split them up into sections such as Memory, Network and Video.

MEMORY OPTIONS If using a newer RPi, remember to remove the # (or omit one) for the value change to have effect. disable_l2cache Disable ARM access to GPU’s L2 cache. Needs corresponding L2 disabled kernel. Default value is 0. gpu_mem GPU memory in megabytes. Sets the memory split between the ARM and GPU. ARM gets the remaining memory. Min 16. Default value is 64. gpu_mem_256 GPU memory in megabytes for the 256 MB Raspberry Pi. Ignored by the 512 MB RP. Overrides gpu_mem. Max 192. Default not set. gpu_mem_512 GPU memory in megabytes for the 512 MB Raspberry Pi. Ignored by the 256 MB RP. Overrides gpu_mem. Max 448. Default not set.

CAMERA OPTIONS If using a newer RPi, remember to remove the # (or omit one) for the value change to have effect. start_x Enables the camera module. disable_camera_led Turn off the red camera LED when recording video or taking a still picture gpu_mem Minimum GPU memory for camera use Example: gpu_mem=128

NETWORK OPTIONS If using a newer RPi, remember to remove the # (or omit one) for the value change to have effect. smsc95xx.macaddr Tells the smsc95xx driver to use a custom mac address instead of using default mac address. Example: smsc95xx.macaddr=B8:AA:BC:DE:F0:12



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VIDEO OPTIONS If using a newer RPi, remember to remove the # (or omit one) for the value change to have effect. sdtv_mode Defines the TV standard for composite output (default=0) 1 for NTSC, 2 for NTSC Japan, 3 for PAL and 4 for PAL Brazil. sdtv_aspect Defines the aspect ratio for composite output (default 4:3=1) 2 for 14:9 and 3 for 16:9. sdtv_disable_colourburst Disables colour burst on composite output. The picture will be monochrome but possibly sharper. hdmi_safe Use “safe mode” settings to try to boot with maximum HDMI compatibility. hdmi_ignore_edid Enables the ignoring of EDID/display data if your display doesn’t have an accurate EDID.

hdmi_force_hotplug Pretends HDMI hotplug signal is asserted so it appears that an HDMI display is attached. hdmi_ignore_hotplug Pretends HDMI hotplug signal is not asserted so it appears an HDMI display is not attached. hdmi_pixel_encoding Force the pixel encoding mode. By default it will use the mode requested from edid so shouldn’t need changing (default is 0) 1 for RGB Limited, 2 for RGB Full, 3 for YCbCr Limited and 4 for YcbCr Full. hdmi_drive Chooses between HDMI and DVI modes. hdmi_group Defines the HDMI type. test_mode Enable test sound/image during boot for manufacturing test. config_hdmi_boost Configure the signal strength of the HDMI interface. Default is 2 on Pi 1 model B and 5 on later boards. display_rotate Rotates the display clockwise on the screen (default=0) 1 for 90 degrees, 2 for 180, 3 for 270, 0x10000 for horizontal flip and 0x20000 for vertical flip.

BOOT OPTIONS If using a newer RPi, remember to remove the # (or omit one) for the value change to have effect.

ramfsfile (string) Ramfs file to load.

disable_commandline_tags Stop start.elf from filling in ATAGS (memory from 0x100) before launching kernel.

ramfsaddr Address to load ramfs file at.

cmdline (string) Command line parameters. Can be used instead of cmdline. txt file. kernel (string) Alternative name to use when loading kernel. Default “kernel. img”. kernel_address Address to load kernel.img file at. kernel_old (bool) if 1, load kernel at 0x0.

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boot_delay Wait for given number of seconds in start.elf before loading kernel; delay = 1000 * boot_delay + boot_delay_ms. Default 1. boot_delay_ms Wait for given number of milliseconds in start.elf before loading kernel. Default 0. avoid_safe_mode If set to 1, safe_mode boot won’t be enabled. Default 0. disable_splash If set to 1, avoids the rainbow splash screen on boot.

Editing the Config.txt File

OVERCLOCKING OPTIONS

Since 2012 you have been able overclock your Raspberry Pi without affecting your warranty but it’s still worth being careful not to load the processor too much. arm_freq Frequency of ARM in MHz. Default 700. gpu_freq Sets core_freq, h264_freq, isp_freq, v3d_freq together. Default 250. core_freq Frequency of GPU processor core in MHz. For models prior to the Pi2, this has an impact on ARM performance since it drives the L2 cache.

initial_turbo Enables turbo mode from boot for the given value in seconds (up to 60) or until cpufreq sets a frequency. Default 0. arm_freq_min Minimum value of arm_freq used for dynamic clocking. Default 700. core_freq_min Minimum value of core_freq used for dynamic clocking. Default 250. sdram_freq_min Minimum value of sdram_freq used for dynamic clocking. Default 400.

h264_freq Frequency of hardware video block in MHz. Default 250.

over_voltage_min Minimum value of over_voltage used for dynamic clocking. Default 0.

isp_freq Frequency of image sensor pipeline block in MHz. Default 250.

temp_limit Overheat protection. Sets clocks and voltages to default when the SoC reaches this Celsius value.

v3d_freq Frequency of 3D block in MHz. Default 250. avoid_pwm_pll Don’t dedicate a pll to PWM audio. This will reduce analogue audio quality slightly. sdram_freq Frequency of SDRAM in MHz. Default 400. over_voltage ARM/GPU core voltage adjust. [-16,8] equates to [0.8 V,1.4 V] with 0.025 V steps. Default is 0 (1.2 V). force_turbo Disables dynamic cpufreq driver and minimum settings.



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Using the Raspbian OS INDEX

Using the Raspbian OS The official operating system for the Raspberry Pi, Raspbian OS, has a fantastic collection of built-in programs and apps to help you get the most from your Pi. Out of the box, the Raspberry Pi is a fully functional desktop computer, complete with a Microsoft Office compatible word processor, spreadsheet program, DTP and more. In this section, discover how to get the Pi online and ensure it’s connected with a unique IP address to your home network. We even show you how to connect to the Raspberry Pi desktop remotely from another computer, whether Windows or macOS. One of the specialties of the Pi is that it’s not limited to the programs and apps that come with the operating system. With a few commands, you can download and install thousands of free programs, and we show you how. This section will also introduce you to several skills you will need over and over again during your Raspberry Pi projects.

34 Take a Tour of PIXEL

50 Transfer Files Using FTP

36 Exploring the Command Line

52 Using the Archiver App

38 Getting Raspberry Pi Online

54 Using the Task Manager

40 Setting Up a Static IP Address

56 Get More from the Terminal App

42 Connect Remotely with VNC

58 Using the Leafpad Text Editor

44 Using the Built-in Applications

60 Using Libre Office to Create Documents

46 Using APT to Install and Remove Programs

62 Edit Images with GIMP

48 Using the File Manager



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Take a Tour of PIXEL PIXEL is the brand new desktop environment for your Raspberry Pi. With PIXEL you can use a Raspberry Pi just like a desktop computer. Only one that’s fine-tuned to learn programming and electronics. GET TO KNOW PIXEL

PIXEL stands for “Pi Improved Xwindow Environment, Lightweight”. It’s a lightning fast and energy saving desktop that looks a lot better than its predecessor. PIXEL is a great interface that makes it much easier to use a Raspberry Pi than entering text commands.

STEP 1

STARTING PIXEL

STEP 2

OPENING PROGRAMS

The PIXEL interface is installed alongside Raspbian OS. By default the Raspberry Pi launches into PIXEL. You will see a photographic picture of a road taken in Iceland.

The Raspbian operating system packs a bunch of programs for you to try out. Click on Menu and choose Programming > Scratch to open the popular tool for learning programming. The program appears inside a window. The buttons in the top right of the window are Iconify, Maximise and Close.

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STEP 3

PROGRAM MENUS

STEP 4

FILE MANAGER

Programs have their own Menu system that appears at the top of each window, and each program can have its own style of Menu system. This is confusing if you come from an OS X background and are used to the Menu bar at the top of the screen.

To view the files stored on your Raspbian OS click on the File Manager icon in the Application Launch Bar (the one that is shaped like a filing cabinet). This opens a window displaying all the files in your home directory. The Directory Tree gives quick access to common folders such as Desktop and Documents.

Take a Tour of PIXEL

STEP 5

MAIN MENU EDITOR

It is possible to remove and add items to the Application Menu using the Main Menu Editor. Choose Menu > Preferences > Main Menu Editor. Add and remove ticks next to programs, and sections you want to include. Use Move Up and Move Down to rearrange items in the Menu.

STEP 6

SHUTDOWN

STEP 3

MENU BAR

STEP 4

FONT

It’s important that you switch off your Raspberry Pi safely. When you are finished with your Raspberry Pi session click Menu > Shutdown. Three options appear Shutdown, Reboot and Logout. Click Shutdown. Wait for the screen to go blank before removing the Micro USB power.

CUSTOMISING THE PIXEL INTERFACE

Personalise your Raspberry Pi and feel at home in your own desktop.

STEP 1

MAKE RASPBERRY PI YOUR OWN

STEP 2

CHANGING THE DESKTOP

Choose Menu > Preferences > Appearance settings to open the Appearance Settings window. There are three sections: Desktop, Menu Bar and System. You can use these to adjust the various options for your system. Notice the Defaults button at the bottom, clicking this returns you to the view you have now.

The most fun thing to start with is the desktop image. Click the button next to picture (displaying “road.jpg”). Double-click any other files to change the desktop. You can click Layout Options and pick No Image if you’d rather have a blank desktop.


You can adjust the look and layout of the Menu bar using the second set of Appearance Settings options. The size of the Menu bar can be adjusted between Large, Medium and Small. And the Position can be set to Top or Bottom. Use the Colour and Text Colour options to adjust the style of the Menu bar.

The System settings can be used to change the Font, Font Size and Highlight Colour and Highlight Text Colour settings. The new font will be displayed in the Menu bar and other parts of the Raspbian operating system. Click OK to finish adjusting the settings, or Defaults to return to the basic settings.


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Exploring the Command Line If you’ve grown up with Windows or OS X then you might never have encountered the command line. This part of the operating system sits beneath the desktop and is used to control a computer using text commands. You’ll need to get familiar with it to use your Raspberry Pi. USING TERMINAL

Despite its graphical PIXEL interface, Raspbian is a Linux operating system and this means you’ll spend a lot of time working with text commands. Far more than you would on a Mac or Windows computer. Using the command line is an important part of learning to use a Raspberry Pi computer.

STEP 1

By default the Raspberry Pi boots directly into the PIXEL interface. Here you use a visual metaphor, files, buttons and so on, to make changes to your computer. The command line is where you control a computer by entering text commands. Click Terminal in the Menu bar to view the console.

STEP 2

You can enter commands into the Terminal to make changes to the computer. This works alongside the PIXEL interface. Enter mkdir Desktop/testfolder and press return. Notice a new folder appears below the Trash on the desktop. Drag it to trash to get rid of it. You can use the Terminal and PIXEL environments alongside each other.

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STEP 3

Another way to switch to a command line environment is to press Control+Alt and F2. This gets rid of the desktop completely and you see just a black screen with text. This is known as a virtual environment and you’re now in tty2 (“tty” is a throwback to teletext writers). You’ll need to enter your login name (“pi” by default) and password (“raspberry” by default).

STEP 4

There are six different virtual environments available. Press Control-Alt-F3 to switch to the third, and Control-Alt-F4 to go to the fourth, and so on. You’ll need to log on to each one in the first instance but can then jump back and forth between them.

Exploring the Command Line

Press Control-Alt-F1 to return to the PIXEL interface. One thing to realise is that PIXEL is just a program running on top of the tty1 session. Open Terminal and enter pkill lxsession. Ouch, there goes your desktop. Don’t worry, enter startx to get it back again. Most of the time you just enter commands into the Terminal window on top of the PIXEL environment.

STEP 5

Some users prefer to use just the command line. Open Menu > Preferences > Raspberry Pi configuration and choose To CLI and click OK and Yes. The Raspbery Pi will now boot into the command line interface. Enter startx to get back to PIXEL, open Raspberry Pi Configuration and choose To Desktop to go back to normal.

STEP 6

USING SUDO

Discovering the power of the super user. One of the most important command line instructions to know is sudo. This command stands for “substitute user do”, sometimes incorrectly called “super user do” and allows you to run a command as another user. Typically this is the root user account, which has more access privileges than your user account.

The first time you enter sudo you’ll be given a warning message. Commands to make, edit and delete files prefaced with sudo can be used to change any file on the system. Sometimes with powerful, or disastrous, results. Be careful. Enter your password and press return.

When you start a command with sudo it is run as the root user and is often used when changing files outside of your user account, such as installing new programs. When you enter sudo you will be asked to enter your user password. Enter sudo -v and press enter.

Be especially careful of any set of commands that use sudo –i. This takes you to root mode, where every command is run as sudo. Your name (normally “pi”) is replaced with “”root”. Root mode is generally considered a bad place to be, so enter exit to get out of it as soon as possible.

STEP 1

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STEP 3

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Getting Raspberry Pi Online You will need to take your Raspberry Pi online to get the most from it. It’s easy to get a Raspberry Pi 3 connected to a Wi-Fi network; or you can even hook your Raspberry Pi directly to a router and get online. CONNECTING TO ETHERNET

No modern computer is an island and connecting your Raspberry Pi to a network and the wider internet is an absolute must. Once your Raspberry Pi is online you will be able to browse the Internet, send email messages and download new software.

STEP 1

The main way to connect a Raspberry Pi 3 to the Internet is using its built in Wi-Fi capability. If you have a Raspberry Pi with just an Ethernet socket, you can connect an Ethernet cable to the socket and run it to a spare socket on your router. If you are at home this will typically be on the back panel of your home modem/router.

STEP 3

You shouldn’t need to do anything else other than connect your Raspberry Pi to your router or modem to get online. Once you make the connection the Network icon in the top right will change into two blue arrows: one facing up, the other down.

STEP 2 If your Raspberry Pi does not have an Ethernet connection, such as the Pi Zero, then you can use a USB-to-Ethernet adapter. Connect this to a spare USB port on the Raspberry Pi. If you have no spare ports you will also need a USB hub. This enables you to connect an Ethernet cable to the Raspberry Pi.

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STEP 4

If you are finding it hard to run an Ethernet cable from your Raspberry Pi all the way to your router consider investing in a home powerline networking kit such as the dLAN made by Devolo (http:// www.devolo.com/).

Getting Raspberry Pi Online

It’s a good idea to know which IP Address your Raspberry Pi is using. This is the one given to it by your router and is used to identify it on your network. Open a terminal window and enter ifconfig. Check for the four digital separated by dots next to inet addr. Ours says “inet addr: 192.168.0.178”.

STEP 5

One way to make sure you are online is to open the Chromium web browser and navigate to a webpage, or choose Menu > Internet > Raspberry Pi Resources. If the page loads correctly your Internet connection is working just fine.

STEP 6

SET UP WI-FI

Connecting your Raspberry Pi to a wireless network. It is possible to connect a Raspberry Pi 3 to the Internet using the built in wireless networking; or, connect a Wi-Fi dongle to any other Raspberry Pi. When you first boot the Raspberry Pi you’ll see two red crosses through the network icon.

If all has gone well you’ll see the Wi-Fi logo symbol in place of the network icon. Use ifconfig in terminal to check your network connection and open the Chromium browser. You will now be able to use your Raspberry Pi online wirelessly.

Click the Network icon in the Menu bar to see all the wireless networks available in the local area. Choose the one you want to connect to. You’ll be asked to enter the password in the Pre Shared Key field. Enter it and press OK to get online.

You can deactivate Wi-Fi by clicking on the Wi-Fi icon and choosing Turn Off Wi-Fi. You won’t be able to get online unless you are also using an Ethernet cable. Click the Wi-Fi icon and choose Turn On Wi-Fi to get back online.

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Setting Up a Static IP Address While this may sound complex, it’s pretty easy if you follow these steps. A static IP ensures other computers can always find your Raspberry Pi. You don’t have to do this, but it often comes in handy. DHCP RESERVATION

Now that you’ve set up your Raspberry Pi and connected it to the network, you should take time to fix its IP address. This will make it a lot easier for you to connect to the Raspberry Pi from a Mac or Windows computer and share files.

STEP 1

When you connect your Raspberry Pi to a network, the router (or modem/router) assigns it a number, known as its IP (Internet Protocol) address. This is a block of four digits and the first three are usually 192.168.0. After that is a digit for each electronic device.

STEP 2

The router typically takes the first address, so it is usually found at 192.168.0.1. That number is reserved for the router. Often you’ll find this number on your router marked “web address”. The router then assigns similar IP address numbers to the other devices you own as they are added to the network, so 192.168.0.2 might be your computer, 192.168.03 your smartphone and so on.

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STEP 3

To find out what number your Raspberry Pi is using click on the Terminal icon and enter ifconfig and press Return. You should find it next to “inet addr:”. The challenge is that the router assigns this number using DHCP (Dynamic Host Configuration Protocol). When the Raspberry Pi is unplugged it reuses the number and your Raspberry Pi may get a different number next time.

STEP 4

It’s better all round if you can get the Raspberry Pi to use the same IP address every time you connect it to the network. You do this using DHCP Reservation. This is where you tell your router to remember the Raspberry Pi address, and only use that address from now on. Start by opening the Chromium Browser and entering 192.168.0.1 to connect to your router’s web interface.

Setting Up a Static IP Address

We’re using a Virgin Broadband router but the process is similar on most routers. Google the name of your router and “DHCP Reservation” to find the router you’re looking for. Enter your admin password (our default password was listed on the back of the router). Click Advanced Settings > DHCP Reservation. In the DHCP Settings section you will find all of the devices connected to your network. Scroll down and find the one with the same IP Address listed in Step 3.

STEP 5

Select the device using the check box on the right and scroll down to the Add Reservation section. It should have filled in the Device Name, MAC Address and IP Address fields. If the Device name is “unknown” change it to “raspberry-pi”. Click Add Reservation to ensure it always uses that IP Address. Click Apply to enforce the changes.

STEP 6

MANAGING YOUR DHCP DEVICES

Now that you have set up a DHCP Reservation, you need to understand how to manage the different devices that may need to use it and connect to the IP. Now that you have set up your Raspberry Pi with a DHCP Reservation it will always connect to the router using that IP Address. You can check this at any time by entering ifconfig into terminal. The router always knows that it is your Raspberry Pi by checking its MAC address. This is the set of six hexadecimal numbers next to “HWaddr” in ifconfig.

Your Raspberry Pi will still have the same IP Address but it isn’t guaranteed to keep it. Restart your raspberry pi by entering sudo shutdown -r now into a Terminal window. When it has restarted enter ifconfig and you’ll find you still use the same IP Address. Over time the router will use other slots for new devices until it reaches its maximum (255 by default). Then it will recycle disconnected devices.

If you decide to free up that IP Address so other devices can use it, you can remove it from the router. Open the router web interface (192.178.0.1) and click Advanced Settings > DHCP Reservation. Scroll down to the IP Lease Table to find the Raspberry Pi. Select the check-box next to it and click Apply and Yes.

Setting up DHCP Reservation is good practice because it ensures you Raspberry Pi is always going to use the same IP Address. It’s also a good idea to write it down or use a label printer to create a label for the Raspberry Pi. You will need this number to connect to the Raspberry Pi via SSH, VPN or FPT (techniques we will use throughout this book).

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Connect Remotely with VNC VNC (Virtual Network Computing) is a powerful technology used to remotely control one computer from another. With VNC set up you can use your Raspberry Pi from your Mac, PC or Linux computer. WHY USE VNC?

The Raspberry Pi is easy to set up and use in projects around the home. But many of these projects don’t need a screen. Some, like Internet doorbells would be silly with a screen attached. VNC lets you control one Raspberry Pi from another.

STEP 1

Setting up VNC used to require entering several commands in Terminal. With PIXEL you can just head into the Raspberry Pi Configuration tool: Menu > Preferences > Raspberry Pi Configuration. Click Interfaces and choose Enable next to VNC. Click OK.

STEP 2

A new icon, marked “VNC”, appears in the top right in the Menu bar. Click it to reveal the VNC Server window. Here you’ll see a section marked “Ready for connections” and beneath it a section “Get Started”. Click the reveal arrow next to Get Started to see the instructions.

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STEP 3

Take note of the IP address under Get Started. It will be the same one as you see using ifconfig in Terminal. You should also look at the VNC Server signature and catchphrase, a list of randomly generated words. Ours is “Loyal normal couple. Simple baker Germany”.

STEP 4

Now switch to the computer that you’re wanting to control the Raspberry Pi from. Open a web browser and visit realvnc. com/download/viewer/. Click Download VNC Viewer and install the software on your computer. You can download VNC Viewer for just about any type of computer; it’s the same program on each machine.

Connect Remotely with VNC

Open VNC Viewer on your Mac, Windows or Linux computer. Enter the IP address you noted in Step 3 in the VNC Server field. Ensure that Encryption is set to “Let VNC Server Choose” and click Connect.

STEP 5

Enter your username and password for the Raspberry Pi (“pi” and “raspberry” by default). Before clicking OK check the catchphrase and signature. This is a good way to make sure you’re connecting securely to the right device. Click OK to start the remote session.

STEP 6

REMOTE CONTROL

Now that you’ve set up VNC Server and connected in VNC Viewer you can start to remotely control your Raspberry Pi. VNC Viewer displays your Raspberry Pi screen on your client computer. The desktop of your computer is replaced by that of your Raspberry Pi. You are now remotely controlling the Raspberry Pi from your computer. If you have both screens set up, you will notice the pointer moving on your Raspberry Pi display as you move the mouse or trackpad, of your computer.

You may also find it useful to turn off Relative Pointer Motion. Press F8 and deselect it from the menu. Now you can move the pointer in and out of the VNC Viewer window and your own desktop with ease. You can also move your pointer up to the top of the VNC Viewer display to view the VNC Viewer Toolbar.

Viewing full screen is useful but you may prefer to view the VNC Viewer screen inside a normal window. Press the F8 button to display a contextual menu inside VNC Viewer. Deselect the Full Screen option and VNC Viewer will be displayed inside a regular window.

One of the joys of owning a Raspberry Pi is being able to use a computer directly; so while VNC is great to set up, we would urge you to continue using your Raspberry Pi. Reveal the VNC Viewer Toolbar and click Close Connection and return to your Raspberry Pi.

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Using the Built-in Applications Everything is now completely set up, and you’re good to go. But where to go first? A great place to start is by checking out the built-in applications. Some are fun, others are practical, and many will help you learn coding. Here are the programs to get started with. THE DEFAULT APPS

The Raspbian operating system comes prepackaged with a stack of useful applications. These make it easy to get up and running with whatever computer project it is you are working on.

STEP 1

Click on the Menu icon to discover the range of software available for your Raspberry Pi. One key aspect of the Raspberry Pi is its use as a learning tool, and there are some great programming tools installed. Choose Menu > Programming to discover all the programming languages installed.

STEP 2

If you’re keen to learn how to code then Scratch is a great place to start. This interactive programming language enables you to create programs in a highly visual fashion. It’s created by MIT and is used by schools worldwide to teach coding basics. There’s a section on Scratch later in the book and you can find more information on the MIT Scratch website: https://scratch.mit.edu.

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STEP 3

You may have heard about Python and both Python 2 and 3 are included with Raspbian. Python is a fantastic language to learn programming with because it has clear syntax and manages memory for you, so all you have to do is code. Most tutorials are for Python 2, so it is better to use that version when learning to code.

STEP 4

Both Wolfram and Mathematica in the Menu > Programming section refer to the same programming language, Wolfram Mathematica 10. While Mathematica is a whole application for development, Wolfram runs just the language inside a Terminal window. Mathematica 10 is a great language for data scientists, although you shouldn’t start learning to code here.

Using the Built-in Applications

Choose Menu > Accessories to view a collection of useful apps and tools to help you use your Raspberry Pi. We’ll take a look at most of these throughout the rest of the book but they enable you to edit text documents, view images and PDF files and manage files and tasks on your Raspberry Pi.

STEP 5

We’ve already mentioned the web browser that you can access using Menu Internet > Web Browser. Connecting your Raspberry Pi also enables you to access various support applications. Choosing Menu > Help > Raspberry Pi Help takes you to the Raspberry Pi help website. Here you will find a lot of information about the Raspberry Pi.

STEP 6

PLAYING GAMES

It may not be an Xbox but the Raspberry Pi comes with some great games for you to play. The Raspberry Pi comes packed with a few games for you to play with. Perhaps the biggest inclusion is a version of Minecraft found under Menu > Games > Minecraft Pi. Click Start Game > New to begin a new game of Minecraft.

STEP 1

The Raspbian operating system also comes with a whole set of Python games to play. Choose Menu > Games > Python Games to view a list of games you can play. These tend to be more simple than Minecraft, and typically are board games, although there is a good Tetris clone called Tetromino.

STEP 2


If you want to play more advanced games you should look online to find more games. Due to Raspbian being a Linux operating system it can run a small selection of games that have been made available over the years, such as this clone of classic Pac-Man. There are many variations of classic games available for the Raspberry Pi.

STEP 3

There are a surprising number of games available for the Raspberry Pi on the Add Remove Software window. This program is found under Menu > Preferences > Add / Remove Software. Here you’ll find lots of apps and programs that you can add to your Raspberry Pi.

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Using APT to Install and Remove Programs When you start to get serious with your Raspberry Pi, you’ll need to install software that is available for Linux, but not part of the Pi Store. These programs are installed from the command line using a service called APT. Learning how to use APT is a vital part of using your Pi. ADVANCED PACKAGING TOOL

Add / Remove Software is great for finding and installing software but most of the time you manage apps on a Raspberry Pi using a program called APT (Advanced Packaging Tool) using the apt command.

STEP 1

To manage the apps on your Raspberry Pi you’ll need to use a tool included with Raspbian called APT (Advanced Packaging Tool). APT is a command line tool so you need to either start your Raspberry Pi in the command line. click on the Terminal icon.

STEP 2

The command used to control packages in Raspbian is apt Type apt into the terminal and press Return to get a description of what the app does. The instructions tell us that the “most frequently used commands are update and install”. You may also hear about “apt-get” which is an older version of the same tool. It works in much the same way.

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STEP 3

The command used to add new software to your Raspberry Pi is apt install followed by the name of the package you want. However, because apt adds (or removes) files outside of your home directory you need to preface apt with the word sudo. Almost all of the time you will need to type sudo apt when using this tool.

STEP 4

Beginning a command with “sudo” runs the command as a super user, “super” meaning the one above your Pi account, rather than one with super-hero properties. However, if it helps you to think of it that way that’s fine. So to install a new program you type: sudo apt install followed by the name of the app you want.

Using APT to Install and Remove Programs

You’re going to install a chess game called Dreamchess. Enter sudo apt install dreamchess and press Return. Descriptive text will run up the screen. You may see “Do you want to continue [Y/n]?” Enter y and press Return to install the application. You’ll find it by choosing: Menu > Games > Dreamchess.

STEP 5

You can use apt-cache to search for apps you can install and remove. Enter apt-cache pkgnames to view all the packages available. Typing apt-cache pkgnames | less enables you to view a page at a time (press any key to scroll). You can use apt-cache search to find packages, enter apt-cache search pong to view a list of Pong games you can install.

STEP 6

MORE APT COMMANDS

The apt command is also used to list, and delete, any apps you have installed. Sometimes you will try to install an app only to get an error that the file cannot be found. In this case you need to update apt so it has the latest links. Enter sudo apt update. This doesn’t update the apps you’ve installed, it just gets a newer listing of apps. To update your apps to the latest versions enter sudo apt upgrade. You’ll often find both commands rolled into one: sudo apt update && sudo apt upgrade.

Packages are uninstalled from your Raspberry Pi using the remove command. Enter sudo apt remove dreamchess to start deleting the chess game that you installed. An alert saying “Do you want to continue [Y/n]?| appears, enter y and press Return to delete the program.

To view the packages you’ve installed you use a different command called dpkg. Enter dpkg --get-selections | grep -v deinstall to view all of the packages on your Raspberry Pi. Place | less after it to view one page at a time. Or dpkg --getselections | grep -v deinstall > ~/Desktop/packages.txt to save the list as a text file on your desktop.

Uninstalled packages using apt doesn’t remove all of the files. Some are left in case you decide to reinstall the program later. To completely remove a package from your Raspberry Pi use the purge command. Enter sudo apt purge dreamchess to remove all of the supporting files. You can also use sudo apt clean to tidy up your packages and free up some drive space.

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Using File Manager Because you’ll be creating programs on your Raspberry Pi, you’ll need to know more about the file system than you would on other computers. One vital tool to become familiar with is the File Manager. This is used to find, move and remove files from your Raspberry Pi. VIEWING AND MOVING FILES

You can move, manage and delete files using the Command Line but like all modern operating systems Raspbian has a program to help you manage your files. Discover how to use the File Manager app.

STEP 1

Raspbian includes a great file management program called “File Manager PCManFM” or just “File Manager” for short. Click on the FileManager PCManFM icon in the Launch Bar or choose Menu > Accessories > File Manager.

STEP 2

File Manager displays the folders in your Home folder (this should match your user name, ‘Pi’ by default). By default you should have Desktop, Documents, Downloads, Music, Picutres, Public, python_games, Scratch and folders. Double-click any folder to open it and view its contents. Click the Parent Folder icon or press Alt-Up Arrow to head back up.

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STEP 3

In the left-hand part of the File Manager sits the Side Pane. By default this displays the Directory Tree, which is another way of navigating the folders on your hard drive. Alternatively click the Side Pane menu and choose Places. Now the Side Pane displays common locations such as Home Folder, Desktop, Rubbish Bin (also known as the Wastebasket), Applications and your SD Card.

STEP 4

You can create a new folder in the current location by choosing File > Create New > Folder or press Shift-Control-N. Enter a name for the folder and click OK. Files and folders can be dragged on top of one another to move them around. You can also drag files to the folders in the Side Pane, which is an easy way to move them back up the folder tree.

Using File Manager

Double-click a file in File Manager to open it with the default app. You can also right-click a file to view compatible applications in Raspbian. Pick an application from the list provided to open it. Click Properties and use the Open with menu to automatically open that type of file with that app in future.

STEP 5

Drag items you no longer want to the Wastebasket to delete them or right-click and choose Move to Trash. To empty the wastebasket and permanently delete the unwanted files double click Wastebasket to open it. Now right-click the black space in File Manager and choose Empty Rubbish Bin. Click Yes in the alert window and the files will be removed.

STEP 6

ADVANCED FILE MANAGER TRICKS

These handy tricks and tips make File Manager more powerful. As you start to move files around you will find navigating between the same folders tiresome. It is possible to open locations in File Manager as tabs, so you can quickly jump back and forth. Click the Create new tab for this folder icon, just below the File menu, and the current folder opens as a tab. Click the tabs to jump between locations.

It’s worth taking time to explore the View menu in File Manager. Here you’ll find a Show Hidden option, which enables you to view hidden files, as well as Sort Files. You can also adjust the Folder View Mode as well as Toolbar, Path Bar, Side Pane and Status Bar.

To view the properties of a file right-click and choose Properties. Here you can view information about the File Type and the Open With application. More importantly, if you click Permissions you can view the permissions associated with that file. The concept of file permissions, especially the ‘Execute’ setting, becomes increasingly important as you become more advanced in using your Raspberry Pi.

There are times when you will want to move files but find you can’t because you don’t have root (sudo) access in File Manager. If you want to open File Manager with root mode choose Menu > Run and enter gksu pcmanfm. File Manager will open and display root and boot() folders. Be careful when running File Manager in root mode, and close it when you are finished.

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Transfer Files using FTP Often you’ll send files to and from your Raspberry Pi from another computer. You can copy these files over on a USB stick, but it’s much easier to bounce the files over the network. For this, you’ll need to learn FTP (File Transfer Protocol). Don’t worry, it’s easy. USING FTP

FTP (File Transfer Protocol) is a technique often used to send files from one computer to another. Most people encounter FTP when they need to upload and download files to and from the Internet, but FTP is great for sending files from your computer to your Raspberry Pi.

STEP 1

Before you get started you’ll need to download an FTP client (a program used to make a connection and transfer files). It doesn’t matter which FTP client you use but our recommendation is FileZilla. On your computer (not your Raspberry Pi) visit https:// filezilla-project.org/ and click Download Filezilla Client.

STEP 2

You need to know the IP (Internet Protocol) address that your Raspberry Pi is using to connect to your local network. Open a terminal window and click Terminal in the Application Launcher. Enter ifconfig and press Return. Look for the four blocks of digits next to “inet addr”.

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STEP 3

The IP address should start with 192.168.0 and be followed by a three-digit number. Ours is 192.168.0.178. That is the number you need to enter into Filezilla so it can find our Raspberry Pi on the network. Head back to Filezilla on your computer and choose File > Site Manager.

STEP 4

Click New Site and enter the IP address you got from the Raspberry Pi into the Host field. Click on the Protocol and change it from FTP to SFTP - SSH File Transfer Protocol. Next click Logon Type and change it to Normal. Finally enter the Username and Password for your Raspberry Pi (“pi” and “raspberry” by default).

Transfer Files using FTP

You may be asked to enter your password. Enter the password for the Raspberry Pi and click OK. The first time you will see an alert: “The server’s host key is unknown”. Select “Always trust this host, add this key to the cache” and click OK. You will now be connected to the Raspberry Pi and can begin to transfer files.

STEP 5

The left side of Filezilla represents the files on your local computer, the PC, whilst the right side represents the files on your Raspberry Pi. The easiest way to transfer files from one side to another is to click and drag the files across. Alternatively right-click on the file on the local side (left) and choose Upload to send it to the currently selected location on your Raspberry Pi.

STEP 6

DIRECT CONNECTION

Linux users can connect directly. Linux users can connect directly to the Raspberry Pi from the Nautilus File Manager. Click Files to start Nautilus and scroll down to Network in the sidebar. Choose Connect To Server to bring up the Server Address window. Enter ssh://[email protected] (use the last three digits that represent your Pi’s IP address).

You can browse the files on your Raspberry Pi from Nautilus like you would with any connected volume. Drag and drop files and volumes from Nautilus to have them transferred directly to your Raspberry Pi. You can only access the files in your home folder though and won’t get root access.

An alert will appear that says “Can’t verify the identity of” and your Pi’s IP address. Click Log In Anyway. Enter the password for the Raspberry Pi and select Remember Password until you logout. Click Connect to log in to the Raspberry Pi. A new connection will appear in Nautilus under Network for your Raspberry Pi.

If you have set up your router with DHCP Reservation, so your Rasbperry Pi has the same IP address each time you power it up, then it’s a good idea to bookmark the connection. Right-click on the IP address and choose Add Bookmark. It appears underneath Bookmarks in the sidebar. Click the Eject icon next to Pi to remove the volume and click the bookmark to reconnect.

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Using the Archiver App Your Raspberry Pi has less storage than some computers, and files are often shared online in a shrunk-down format. These are compressed and uncompressed (so they can be used) using an app called Archiver. Discover how to expand and compress files with this handy app. EXPAND AND COMPRESS FILES

Many files are compressed when sent across the Internet. The Raspberry Pi has a built in utility called Archiver used to expand and compress files.

STEP 1

Compressed files can be viewed in the File Manager application and they often end with a .zip extension (although other compressed file types exist, including bz2, tar and gzip). Compressed files can be identified by the opening box icon. Double-click a compressed file to open the Archiver app.

STEP 2

If the Choose Application window appears, open Accessories and highlight Archiver. Tick “Set selected application as default for this file type” and click OK>. Archiver displays the folder inside the compressed file.

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STEP 3

Double-clicking a file inside Archiver temporarily expands that file and opens it in a compatible program. You can also right-click files and choose Open With to view them in the program of your choosing (just like an uncompressed file in File Manager).

STEP 4

Right-click individual files and choose Extract to open the Extract Files menu. Click the small file icon next to the path in Extract To and choose a destination for the file. Click Extract to expand the file. A copy remains inside the compressed file, but now you will be able to access the file directly from inside Raspbian.

Using the Archiver App

If you wish to extract the entire archive Press Control-A to select all of the files and choose Action > Extract. Choose a location using the Extract Files window and click Extract. Ensure that the “Extract files with full path” option is selected. All of the files will be expanded from the compressed file into the location you choose.

STEP 5

Expanding compressed files doesn’t remove the original file, which will remain on your Raspberry Pi’s SD Card, typically in the downloads folder. To save space you should delete the file. Rightclick the file to reveal the contextual menu and hold down Shift. Move to Trash turns into the Remove command. Select Remove and click Yes to immediately delete the file.

STEP 6

CREATE ARCHIVES

Compress files to save space on your Raspberry Pi. With space on your Raspberry Pi at a premium you can use Archiver to compress files and save space. This is handy if you want to put files into storage, but not delete them. If you have just a few files to compress, locate them using File Manager and select them. Now right-click and choose Compress.

STEP 1

The Create a new archive window appears. Use the Places window to select your folder and give it a name (click New Folder to create a new path for the file.) The Archive Type menu in the bottom left is used to choose an archive type; bz2 is the default type but tar enables you to add files. Click Create to turn the files into the compressed archive.

It is possible to add files to a compressed archive. This is handy if you use a file to archive files that you add to on a regular basis, as part of space saving and housekeeping. Open the compressed file in Archiver and choose Action > Add. Use the Add Files window to locate the extra files and click Add.

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It is possible to expand archived files from the command line using the unzip command (for zip files) and tar -xvf command (for tar files). You need to enter the name of the file you want to unpack and path to a folder you want to create. Such as: tar -x archive.tar ~/Documents/photos.

STEP 4


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Using the Task Manager Task Manager is a great app that shows all the different programs and processes running on your Raspberry Pi. It is used to keep an eye on things, and also to solve problems. As you start to use your Pi, you’ll become far more adept at managing processes. MANAGE PROCESSES

The Raspbian operating system is made up of lots of processes, known as “commands”. These can all be viewed, managed and forced to quit using the Task Manager program.

STEP 1

The Task Manager app is a great way to get an overview of all the different processes that make up your Raspbian operating system. Choose Menu > Accessories > Task Manager to open the Task Manager app. At the top you will see how much CPU and Memory is being currently used by your system.

STEP 2

All the processes are listed in the Command column. Next to this is the User that owns the process. Next is the percentage of CPU that it is currently taking up; note that it is possible for processes to take up more than 100 per cent of CPU. If your Raspberry Pi is running slowly click the CPU column to arrange by CPU usage.

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STEP 3

RSS (Resident Set Size [of Memory]) is the amount of RAM that the process is currently taking up. Sorting by the RSS column enables you to view which processes are taking up memory space. VM-Size is the amount of virtual memory used by the process; this is memory that is created virtually using the space on the SD Card.

STEP 4

By default Task Manager shows just the tasks that are owned by the current user. There are more processes used by the root system and if you have multiple users they may have tasks too. Choose View > Show Root Tasks and View > Short Other Tasks to view these other processes. It’s best to leave Root Tasks alone if possible, as quitting them can cause Raspbian to become unstable.

Using the Task Manager

The More Details button can be used to switch between a simple view that displays just the Command, CPU, RSS and PID (Process Identifier) and the more detailed view. Clicking More Details is handy if you just want to view simple details in a smaller window while working with other apps.

STEP 5

It is possible to assign priorities to tasks to decide which ones Raspbian gives preference too. This is handy if you have a process that you want to keep open but not interfere with other programs. Right-click on a process and choose Priority and between -10 (not important) to 10 (very important). The default for all processes is 0.

STEP 6

QUITTING AND KILLING Kill or terminate unruly processes.

One of the most common reasons for opening Task Manager is to help deal with an unresponsive process. If a program crashes it is usually because a process has become unresponsive (the rest of the operating system keeps running). Right-click a process to view a list of commands that can help.

If a process is frozen and you want to end it, first try to use the terminate command, rather than Kill. Right-click the process and choose Term. The terminate command sends an alert to the program that it is about to close down, so the program can attempt to save any data. It’s a safer way to end a program than Kill.

Stop and Continue can be used to temporarily halt and then resume a process. Right-click a process and choose Stop to halt the process. The CPU usage of the process should drop to 0% but the RSS will stay because it remains in memory. Right-click and choose Continue to start the process running again.

Killing a process is the way to stop runaway and unresponsive processes in their tracks. To end a process in this manner right-click it and choose Kill. The process will be sent a series of signals to instantly end, each gets more severe until a SIGKILL (kill signal) is sent and the program is ejected. Be careful when using Kill because some processes may be in use by Raspbian.

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Get More from the Terminal App Terminal is an app in Raspbian that enables you to access the command line and issue text commands to your Pi. You’ll spend a lot of time in terminal, so it’s a great idea to get to know the app and set it up to work your way. CUSTOM TERMINAL

You’ll spend a lot of time in Terminal, so why not get to know it a bit better and set it up to work just the way you want.

STEP 1

Start Terminal by clicking the Terminal icon in the Application Launch Bar. You can also start Terminal by pressing Control-Alt-T or choosing Menu > Accessories > Terminal. Terminal emulates the old style video terminals from before desktop interfaces; so by default it displays bright (mostly green) on a black background.

STEP 2

The first thing most people overlook is the ability to run multiple terminals at once in different tabs. Choose File > New Tab (Shift-Control-T) to create a new tab. Navigating multiple directories simultaneously can be a challenge in Terminal and tabs makes it that much easier.

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STEP 3

Naming tabs makes them much easier to recognise. Choose Tabs > Name Tab and enter a name for the tab such as “Home” or “Downloads”. Click OK to set the name. You can quickly switch between tabs using Control-Page Up and Control-Page Down and rearrange them using the Tabs Move Tab Left / Move Tab Right options.

STEP 4

Choose Edit > Preferences to personalise the look and feel of LXTerminal. One of the best tricks is to click Background and drag the Opacity slider to the half-way point. This enables you to view through the terminal background and see the windows below. You can also personalise the colour of the background.

Get More from the Terminal App

While still in Preferences click the Display tab. Here you can adjust the Tab panel positions, placing them on the Left makes them more prominent. You can also adjust the scroll-back line count. This is the number of lines you can scroll up with using the mouse, not the history accessed by the Up and Down arrows.

STEP 5

If you prefer a more minimalist approach try moving the Tabs to the bottom and selecting the Hide scroll bar, Hide menu bar and Hide Close button options. When combined with a low opacity background this makes for a subtle terminal window. You can still access menu settings using a right-click on the mouse.

STEP 6

CONNECT USING SSH

Use a different computer to control your Raspberry Pi. If you have your Raspberry Pi on the same network as a Mac or Linux-based computer, you can control it using the Terminal program on that computer. We’re going to use Terminal in macOS here but the process is the same on a Linux machine. Open the Terminal app on your computer.

Switch back to Terminal on your Mac or Linux machine and enter ssh [email protected] (using your own IP address). The “pi” bit is the name of the default user account, so if you have changed that it needs to match your user account on the Raspberry Pi. You’ll be asked for a password. This is the password that you use to log in to the Raspberry Pi (not your Mac or Linux computer).

Enter ifconfig into the Terminal app on your Raspberry Pi. This will let you know which IP address it is using. Look for the four blocks of digits following “inet addr:’. They should begin with 192.168.0 followed by a three-digit number. Ours is 192.168.0.179. You need to use that number in Terminal on our Mac to connect.

You are now logged in to your Raspberry Pi and can enter commands directly into the Terminal on your Mac or Linux computer. Unlike remote networking you don’t see the commands being entered on the screen of the Raspberry Pi, you are accessing the computer from behind the scenes. Many people prefer to set up the Raspberry Pi so they can control it from a more powerful computer. Enter exit to close the connection.

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Using the Leafpad Text Editor Text files are very important in the Raspberry Pi. As well as writing documents, you use text files to adjust settings, create scripts and to write programs. Part of the joy of owning a Pi is learning programming, so you should spend time getting to know Leafpad. EDITING TEXT

You’ll spend a lot more time editing text and files in Raspbian than you’re probably used to on a Windows or Mac computer. Raspbian comes with a built-in text editor called Leafpad.

STEP 1

Choose Menu > Accessories > Text Editor to open the Leafpad application. It works very much like other text editors where you enter text into the window. There is no built-in spell checker or grammar checker in Leafpad; we’ll look at LibreOffice later for more powerful document editing. Rather than being used for word processing, Leafpad is typically used to edit configuration and code files.

STEP 2

Save your new file by choosing File > Save As (or press Shift-Control-S). Enter a name for your document in the Name field and use the Save in folder window to select a location. Pay attention to the Character Encoding and ensure that it is set to UTF-8 in most instances. UTF-8 ensures that your document uses Unicode character formatting. Visit unicode.org for more information on Unicode formatting.

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STEP 3

Next to Unicode are three options: LF, CR+LF and CR. LF stands for Line Feed and CR stands for Carriage Return. These are different ways that a document knows when it has reached the end of each line. You should ensure that LF is the selected option, as that is what Unix and modern Mac systems use. CR+LF is used by Windows systems and only very old documents use just the CR standard.

STEP 4

When opening a document (File > Open) you should ensure that character coding is set to Auto-Detect. This selection will match the various character encoding formats available. The other common standard you will encounter is ISO-8859-1 and occasionally ISO-8859-15, which features European characters such as the Euro sign. If you open a document and some of the symbols are garbled then try to use a different Character Coding standard.

Using the Leafpad Text Editor

It is possible (though rare) to hook a Raspberry Pi up to a printer and print out documents. More commonly you use the Print command to save a file in the PDF format. Using PDFs enables you to share and archive files while preserving formatting. Choose File > Print and select Print to File. Ensure Output format is set to PDF and use the Name and Save in folder options to set a location for your document. Click Print to save the file as a PDF.

STEP 5

You will mostly use Leafpad for editing code, so it’s a good idea to ensure that Word Wrap is turned off and Line Numbers are turned on. Click options and ensure that there isn’t a tick next to Word Wrap and place one next to Line Numbers. Turn on Auto Indent, this ensures that the next line down starts indented to the same space (four characters by default). This option is useful when programming.

STEP 6

EDIT TERMINAL

Quickly edit your files from terminal. You can create text files inside the terminal using a built-in text editor called Nano. You can use Nano to open files or create new ones. Enter nano fizzbang.py to create a new document in your current folder called “fizzbang.py”. The .py extension tells Raspbian that this is going to be a Python program. The command line disappears and a basic text-editing app enables you to create and edit text.

Files already in Raspberry Pi are opened by typing nano and the file name. If you enter nano fizzbang.py again the file is reopened in Nano. You can edit and output it the same way. However, be careful to enter the name exactly right, with the same capitalisation, or you will create a new blank document. You can also use sudo nano to edit files that you need root permission for.

Enter your text into Nano to start typing out your document. The Nano text editor is very old and doesn’t follow many of the conventions of modern programming applications. You save a file by pressing Control-O to output its contents. At the bottom, the File Name to Write alerts will appear. Check that it is correct and press Return. Press Control-X to exit the Nano application.

It can be a pain to switch to Leafpad or Nano and open a file just to view, and quickly edit, its contents. Instead use the cat (concatenate) command to quickly view the contents of the file inside Terminal. Here you are viewing the contents of your fizzbang.py file in terminal after entering cat fizzbang.py.

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Using LibreOffice to Create Documents The text editor is great for scripts and coding, but the Raspberry Pi also comes with a great office suite called LibreOffice. This can be used to create and edit word documents and spreadsheets. The Raspberry Pi may be small, but it’s a powerful computer. JUST LIKE MICROSOFT OFFICE

Leafpad and Nano are great for editing text files but if you want to create a more complex document on your Raspberry Pi then LibreOffice is the app to use. It’s just like having Microsoft Office on your Raspberry Pi.

STEP 1

LibreOffice is included with Raspberry Pi and PIXEL so there is no need to install it. Click on Menu > Office. Inside you will find five apps: Base, Calc, Draw, Impress and Writer. These are functionally similar to Microsoft Office apps. Base is a database program, Impress is presentation software like PowerPoint; Calc is Excel and Writer is similar to Microsoft Word.

STEP 2

Choose Menu > Office > LibreOffice Writer to open the word processing application. You can instantly tell that this is a more functionally powerful application than Leafpad. The menu has more detailed tools such as Insert, Format and Table and a selection of Menu bar icons enable you to fine-tune your text documents.

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STEP 3

Text is entered into LibreOffice just the same as any other text editor , but you have a much greater range of formatting options. The Apply Style menu can be used to add Heading 1 and Heading 2 styles to text, while the Numbering and Bullets icons can be used to add lists. Options like these make LibreOffice Writer a good place to create text for online blogs and articles.

STEP 4

Another important feature in LibreOffice is its ability to mix images with text. Add an image to your document by choosing Insert > Picture > From File. Use the Insert Picture window to locate the file, and click Open. The image will be inserted at the cursor , but you can use the green drag handles to resize it and click and drag to reposition it.

Using LibreOffice to Create Documents

Choose File > Save As to save your Writer document. In the bottom right you will see All Formats but this is used to filter the files shown in the window. Click File Type in the bottom left to choose the file type you want to save the document as. LibreOffice uses the .odt extension (Open Document Text) by default. You can choose Microsoft Word and other formats instead.

STEP 5

You can print out documents created in LibreOffice. Connect a printer to your Raspberry Pi with a USB cable. Choose File > Print. It is also possible to export a document to PDF format, suitable for sharing. Choose File > Export as PDF.

STEP 6

CHECK YOUR SPELLING Set up the LibreOffice spell checker.

One of the big advantages Writer has over other Raspberry Pi text editors is the presence of a spell checker. However, you don’t have the languages installed so it doesn’t work automatically. Open the browser and enter this URL to get the files http:// extensions.libreoffice.org/extension-center/americanbritish-canadian-spelling-hyphen-thesaurusdictionaries/releases/3.0. Scroll down and click the first link under Available Downloads.

STEP 1

There are usually a selection of downloads available. Each ends with the .oxt extensions. Click the one you want, typically the one with the most words, and it will be downloaded to your SD Card. The file will be saved into your Downloads folder automatically.

STEP 2


In LibreOffice choose Tools > Extension Manager and click Add. Click Pi in the Places folder and select the Downloads folder to display the dictionary file. Select it and click Open and it will be added to the Extension Manager. Wait for the progress bar at the bottom to finish and click Close.

STEP 3

Choose Tools > Language > For All Text and either English (UK) or English (USA). Now choose Tools > Spelling and Grammar to check the document or click the Spelling icon. You can also check spelling as you type by clicking the AutoSpellcheck icon in the Menu bar. Now as you type words wrongly, they will appear with a red underline, enabling you to correct spellings as you type.

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Edit Images with GIMP The name may be funny, but this image editing app is incredibly serious. The Raspberry Pi is perfectly adept at photo editing, and you can use GIMP to create icons, images and works of art for your programs. GET TO KNOW GIMP

Your Raspberry Pi can display images with its built-in Image View app but for any image editing you’ll need GIMP (GNU Image Manipulation Program). GIMP is a powerful software package for photo editing and is a great tool to install on your Raspberry Pi.

STEP 1

Open terminal and enter sudo apt install gimp to download and install the GIMP package. An alert will appear saying: “after this operation, 117 MB of additional disk space will be used. Do you want to continue [Y/n]?” Enter y and press Return. GIMP will now be installed in Raspbian. GIMP is a lot larger than most programs you’ll install, so the installation takes longer.

STEP 2

When the installation has completed you will find GIMP under Menu > Graphics > GNU Image Manipulation Program. It has a more detailed interface than many Linux programs with two boxes, Tool Options and Brushes offering a range of image editing options. Users of software like Adobe Photoshop will feel right at home and it’s ideal for image editing.

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STEP 3

Images can be opened in GIMP using File > Open or by right-clicking on files in File Manager and choosing GNU Image Manipulation Program. You can open multiple images at once in GIMP but each opens inside a different window. Choose Window > Single Window Mode to gather them together. Click on the tabs at the top of the screen to switch from one image to another.

STEP 4

You can perform powerful edits in GIMP but we don’t have space to go over them all. Probably the most useful you’ll find is Colours > Levels. This window enables you to adjust the tonal range and colour balance of an image. Drag the left and right handles in slightly and slide the centre handle to the right to improve the contrast of an image.

Edit Images with GIMP

To crop an image click the Rectangle Select Tool and drag a square on the image. Choose Image > Crop To Selection to remove the unwanted parts of the image. Use the Image > Scale Image and Image > Canvas Size options to adjust the image to specific sizes. Cropping and resizing images is a vital technique to know when working on websites.

STEP 5

There are a huge range of image effects and filters you can add to images using GIMP. Far more than we have room to cover here. Try Filters > Artistic > Cartoon to give your image a black outline or Filters > Artistic > Oilify to simulate a painted artwork. Take a look at www.gimp.org/tutorials for creative inspiration.

STEP 6

EXPORTING IMAGES

Save your images for use in a website. Images are saved using File > Save As in the xcf format (Experimental Computing Facility). This is GIMP’s native format so should only be used to save files you want to view and work on in GIMP.

The Export Image as JPEG window appears, displaying a Quality slider. The Quality range is from 0 (very poor) to 100 (perfect). While you might be tempted to set the quality at 100, reducing it slightly will create much smaller files. Smaller files ensure that your web page loads much more quickly. You can typically reduce the Quality to 80 and get a much smaller file with little discernible difference.

If you want to save files for use in projects, such as websites, use File > Export. Click the File Type option and choose a file type; typically you will use JPEG for web images. Choose a Name and location and click Export.

Right-click a JPEG image in the File Manager and choose Open With. Expand Internet and choose Chromium Web Browser and OK. This enables you to see how it will appear when you add it to your website. You can also view images more quickly by right clicking and choosing Image Viewer. You can use Save File As in Image Viewer to quickly change the image format.

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Getting to Know Unix INDEX

Getting to Know Unix The Raspbian operating system is Linux based, which in turn is a Unix-like OS. Having knowledge of how Unix works, how the file system is structured and how you go about finding your way around the system is vital to every Raspberry Pi user. Unix, and thus Linux, is very different to that of Windows and in some cases even macOS. Being able to list and move files and folders, delete files, create directories, edit text files and even view the system processes can help you massively as you become more adept at using the RPi; and of course it aids you in setting up fantastic future projects.

66 What is Unix?

82 Editing Text Files

68 Understanding Unix

84 Getting to Know Users

70 Using the Unix Filesystem

86 Ownership and Permissions

72 Listing and Moving Files

88 Useful System and Disk Commands

74 Creating and Deleting Files

90 Managing Programs and Processes

76 Create and Remove Directories

92 Input, Output and Pipes

78 Copying, Moving and Renaming Files

94 How to Customise Unix

80 Using the Man Pages



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What is Unix? Unix is hard to define but vital to learn if you want to use your Raspberry Pi, or learn programming in general. It’s the engine that sits beneath Linux (the OS that Raspbian is based on). When you enter text into the command line, it is often called a “Unix command”. UNDERSTANDING UNIX

Unix is a family of operating systems; one of which is Linux: the system that underlies the Raspbian OS. Because Linux is a Unix-like system, you can use Unix commands to control it. This is the Linux Command Line, and learning how to use it is vital to controlling a Raspberry Pi.

STEP 1

You can enter Unix commands into the Terminal app inside the LXDE desktop, as you have done throughout this book. For this Unix section you will work completely in the command line though. You can quit the desktop by entering pkill x into the terminal. The desktop will close down leaving you back in the command line.

STEP 3

Unix is still owned by AT&T. This brings us to GNU, which is a recursive acronym that stands for “GNU Is Not Unix”. GNU looks, and works, just like Unix but contains no Unix code underneath. GNU is free and open source. One key aspect of GNU is that the kernel, the code that sits between the OS and the hardware, can interact with non-GNU systems. So it’s extremely flexible.

STEP 2

It’s important to get some terms cleared up. Unix is hard to define. Originally Unix was developed by AT&T employees around 1970 and was used to control mainframe computers. For legal reasons AT&T couldn’t sell it; so they gave copies away to people who asked. It then spread to other companies and universities who improved it. Over time different versions of Unix appeared, some free and others owned by companies like Sun Oracle or IBM.

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STEP 4

Linux is a base for an operating system designed in the 1990s by Linus Torvalds but developed by a large and dedicated open source community. Linux is also referred to by some as GNU/Linux because it is based on a modified version of GNU. Linux is used as the base for an operating system such as Raspbian. So when you open the command line in Raspbian you are using Linux.

What is Unix?

STEP 5

The Linux command line accepts Unix commands but is not actually Unix; it’s Linux, which is a Unix-like system based on GNU (which is also not Unix). Everybody says Unix because on the surface it’s by-and-large indistinguishable from Unix. So the terms Unix, Linux command line, Unix-like and GNU are pretty much used interchangeably.

STEP 6

So learning Unix is vital to learning how your Raspberry Pi works. Even though Raspbian doesn’t actually contain Unix code, it uses the Unix language underneath the LXDE interface. In the next few tutorials we’ll take you through Unix step-by-step so you can get to grips with it.

GETTING SYSTEM INFORMATION Discovering system information in Unix.

One of the best things you can do to get started is to enter some commands in Unix to get some information about your Raspberry Pi. Start by entering uname -s. This gives you the kernel, which is Linux. Now enter uname -o to see the operating system: “GNU/ Linux”. Finally enter uname -a to see all of the system information.

STEP 1

When the Raspberry Pi system boots a lot of text heads up the screen. These are messages from the kernel and you can see them using dmesg. There’s usually too much text to fit on the screen so use dmesg | less to view the text one screen at a time. Press any key to move to the next screen of text and press q to exit the text.

Get information on your Raspberry Pi’s hardware using the command cat /proc/cpuinfo. This displays the processor, model name and CPU architecture information. If you have a Raspberry Pi 3 there will be four sections, one for each processor core. Earlier models of Raspberry Pi will have just one section.

STEP 3

STEP 2

Enter cat /proc/meminfo to view detailed information about the memory installed on your Raspberry Pi. This tells you the total and free amount of memory. You can also use vmstat to display a compact summery of system activity. Entering top runs a loop on system activity, similar to using Task Manager. Press Control-C to exit the top display.

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Understanding Unix Take control of your Raspberry Pi by learning its language.

Owner Each file has an owner, typically the person who created the file. You’ll usually have two owners: pi and root. Pi is for files and directories created by your default user account, and root is for all the system files.

Permissions At the start of each item in our list is a list of letters and hyphens. These represent the permissions for each file, and who can read, write (edit) and execute (run) the file. It look complex but we’ll explain how to understand and edit permissions in simple steps.

Running Commands Unix has a wide range of commands and tools built into it. You can manage your entire Raspberry Pi from the command line. The desktop environment is, in many ways, just a skin over the top of this command line.

Command Line You can enter powerful, and complex, commands into Unix. These can be simple, like our request to get the CPU temperature, or extremely complex.

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Understanding Unix

Navigation This pwd command lists the current working directory. This is the equivalent to the folder you are looking at in File Manager and any files you create, move, edit or delete will be in this directory by default.

List Directory You view the contents of the current working directory using the ls command (it stands for “list”). The “-l” following it is an option, in this case the ‘-l” option gives us the long list format which displays more information.

Navigation You move from one directory to another using the cd command along with the name of the directory you want to move to.

Running Commands You can enter powerful, and complex, commands into Unix. These can be simple, like our request to get the CPU temperature, or extremely complex.


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Using the Unix Filesystem The idea of files and folders and moving around them in a text-based command line may be a bit weird at first. Don’t worry, this is how everybody did things in the old days, and it’s easy enough once you get your head around it. Here’s how to navigate the Unix filesystem. GETTING AROUND

For people raised on desktop computers, the idea of viewing and moving files and directories in a text environment can be daunting. But don’t worry, it is easy to view and move files and directories and navigate the filesystem. Here we’ll show you how.

STEP 1

First we’re going to look at directories and the directory path. A directory is the same thing as a folder, only in Unix it’s always called a directory. Directories are placed inside each other using a ‘/’ character. So when you see “/home/pi” it means the pi directory is inside the home directory. Enter clear and press return to clean the screen. Now enter pwd. This stands for Print Working Directory and displays “/home/pi”.

STEP 3

Enter ls to view the contents of the current directory. You should see Desktop, Documents, and Downloads and Scratch in Blue. You may also see other items depending on how much you have used your Raspberry Pi. The colour code is worth knowing: directories are blue while most files are white. As you go on you’ll see other colours: executable files (programs) are bright green, archived files are red and so on. Blue and white are the two you need to know to get started.

STEP 4

STEP 2

When you log in to your Raspberry Pi, you don’t start at the base of the hard drive, known as the ‘root’ (also known as the topmost directory). Instead you begin inside your user directory, which is named ‘pi’ by default and is itself in a directory called ‘home’. Directories are indicated by the ‘/’ symbol. So, “‘/home/pi’” tells you that in the root is a directory called home, and the next “‘/’” says that inside “home” is a directory called “pi”. That’s where you start.

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Now we’re going to move from the pi directory into the Documents directory. Enter cd Documents. Note the capital “D”. Unix is case-sensitive, which means you have to enter the exact name including correct capitalisation. The “cd” command stands for “change directory”. Now enter pwd again to view the directory path. It will be /home/ pi/Documents. Enter ls to view the files inside the Documents directory.

Using the Unix Filesystem

So how do we get back up to the pi directory? We use a command “cd ..” – two dots in Unix means the directory above, also known as the “parent” directory. Incidentally a single dot “.” is used for the same directory. You’ll never use “cd .” to switch to the same directory, but it’s worth knowing because some commands need you to specify the current directory.

STEP 5

The “ls” and “cd” commands can also be used with more complex paths. Enter ls Documents/Pictures to view the contents of a Pictures directory inside your Documents directory. You can switch to this directory using cd Documents/Pictures; use cd ../.. to move back up two parent directories.

STEP 6

ABSOLUTE VS RELATIVE PATHS

It is important to know the difference between the working directory, root directory and home. There are also two types of path: Absolute and Relative. These are easier to understand than they sound. Let’s take a look… By default, commands like “ls” use the working directory. This is the current directory that you’re looking at and is set to your home directory by default (/users/pi). Using “pwd” (Print Working Directory) lets you know what the working directory is, and using “cd” changes the working directory.

The second command (“ls /Documents/Pictures”) attempts to list the content of Pictures in a directory called Documents inside the root directory (because the path started with ‘/’, which is root). There is typically no Documents directory in root, so you will get a “No such file or directory” error. Starting a path with ‘/’ is known as an “absolute path”, while starting without the ‘/’ is known as a “relative path” because it is relative to your working directory.

The root directory is always ‘/’. Entering ls / lists the contents of root, and entering cd / switches to the root directory. This is important because there is a difference between “ls Documents/Pictures” and “ls /Documents/Pictures”. The first command lists the contents of the Pictures directory in Documents inside the working directory (which, if you are in the home directory, will work).

There is also an absolute path shortcut to your user directory, and that is the tilde “~” character. Entering ls ~ always lists the contents of your home directory, while “cd ~” moves straight to your home directory, no matter what your working directory is. You can also use this shortcut wherever you are: enter ls ~/Documents/ Pictures to display the contents of the Pictures.

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Listing and Moving Files Because Unix is text-based, you won’t see all of your files and directories, and you can’t drag items around as you can in a file manager. Don’t worry though, Unix has two great commands that will help you out. LOOKING AT FILES

Computer operating systems are files and directories. While you might be used to seeing your own files, the average modern OS keeps other files out of sight. In Raspbian you get access to every file on your system, so learn how to manage files wisely.

STEP 1

We’ve already looked at “ls”, which lists the files in the working directory, but you are more likely to use a command like “ls –l”. The bit after the command (the ‘-lah’) is known as the argument. This is an option that modifies the behaviour of the command.

STEP 2

The “-l” argument lists files and directories in long format. Each file and directory is now on a single line, and before each file is a lot of text. First you’ll see lots of letters and dashes, like ‘drwxr-xr-x’. Don’t worry about these for now; they are known as ‘permissions’ and we’ll come to those later.

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STEP 3

After the permission letters come a single number. This is the number of files in the item. If it’s a file then it’ll be 1, but if it’s a directory it’ll be at least 2. This is because each directory contains two hidden files; one with a single dot (.) and one with two dots (..). Directories containing files or other directories will have a higher number.

STEP 4

Next you’ll see the word “pi” listed twice on each line. This refers to the user rather than the name of your computer (your default username is “pi”). The first is the owner of the file, and the second is the group. Typically these will both be the same and you’ll see either ‘pi’ or ‘root’. You can enter ls -l / to view the files and directories in the root directory that belong to the root account.

Listing and Moving Files

The next number relates to the size of the file, in bytes. In Unix each text file is made up of letters, and each letter takes up a byte. So our names.txt file has 37 bytes, and has 37 characters in the document. Files and directories can be extremely large, and hard to determine, so use “ls –lh”. The “h” argument ‘humanises’ the number, making it easier to read.

STEP 5

Finally, you should be aware that there are many hidden files in Unix. These are listed using the “-a” argument. Hidden files and directories begin with a dot (.), so you should never start a file or directory with a dot, unless you want to hide it. Typically you’ll combine all three arguments together into the command “ls –lah”.

STEP 6

SOME COMMON DIRECTORIES

Now that you know how to view the contents of your hard drive you’ll start to notice a lot of directories with names like bin, sbin, var and dev. These are the files and directories that you are kept away from on a Mac, and won’t encounter on a Windows PC. Enter ls -lah / to view all of the files and directories, including the hidden items, in the root directory of your hard drive. Here you will see all the items that make up your Raspbian OS (which is a version of Linux). It’s worth taking the time to know some of them.

Entering ls /home displays the contents of your home directory, which contains pi; the directory that you start in. So, entering ls/home/pi is the same as just “ls” from the default home directory. This is where you are expected to place most of the documents you create. Don’t confuse home with “usr”; the /usr directory is where find you find program tools and libraries.

Bin is a directory that stores ‘binaries’. This is the Unix way of saying programs or applications. Sbin is for system binaries, which are the programs that make up your system. Dev contains references to your devices (hard drive, keyboard, mouse and so on); Etc contains your system configuration files.

Lib is a directory that contains libraries of code that are referred to by other programs (different programs share files in Lib). “Var” is short for various, which is mostly files used by the system, but you may need to work with items here. Finally there is a directory called “tmp”, which is for temporary files; files placed here are on your system for the short term and can be deleted from the system.

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Creating and Deleting Files Discover how to make and remove files on your Raspberry Pi computer. Creating and deleting files is a normal part of everyday computing, but you need to be very careful when deleting items in Unix. In this tutorial, we’ll show you how to safely delete files. CREATING FILES

Once you learn to recognise the files and directories that make up Raspbian OS, it’s time to discover how to make your own. Knowing how to make, edit and delete files and directories is essential if you want to make your own projects.

STEP 1

We’re going to create a file using a command called Touch. Touch is an interesting command that reaches out to a file, or directory, and updates it (this changes the system time as if you’d just opened the file). You can see Touch in access using “ls –l” and checking the time next to a directory (such as Scratch).

STEP 2

Now enter touch Scratch and ls –l again and notice that the time has changed. It now matches the current time. You might be wondering what this has to do with creating files or directories. Touch has a second, more popular, use, which is to create files.

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STEP 3

If you try to touch a file that doesn’t exist, you create a blank file with that name. Try it now. Type touch testfile and ls –l to view the files. You’ll now have a new file in your home directory called “testfile”. Notice that the size of the file is 0, because it has nothing in it.

STEP 4

A quick word about file names: remember that Unix is case sensitive, so if you now enter touch Testfile (with a capital T), you won’t update “testfile”; instead you’ll create a second file called “Testfile”. Enter ls –l to see both files. This is confusing, so most people stick with using lowercase letters at all times.

Creating and Deleting Files

Another important thing to know is never to use a space in your file names. If you try to enter touch test file, you create a document called “test” and another called “file”. Technically there are ways to create files containing a space but you should always use an underscore character (“_”) instead of a space, such as “touch test_file”.

STEP 5

Here are some other files names to avoid: #%&{}\<>*?/$!’”:@+`|=. The full stop (.) is used to create an extension to a file; usually used to indicate a file type, such as textfile.txt or compressedfile.zip, and starting a file with a full stop makes it invisible. Don’t use full stop in place of a space though; stick to underscores.

STEP 6

REMOVING FILES

We’ve created some files that we don’t want, so how do we go about removing them? It turns out that deleting files in your Raspberry Pi is really easy, which may be a problem, so be careful. Enter ls –l to view the files in your home directory. If you’ve followed the steps before then you should have three files: “test”, “testfile”, and “Testfile”. We’re going to get rid of these items because they were created as an example.

We’re going to use a wildcard (*) to delete our next two files, but again this is something you really need to do with care. First use “ls” to list the files and make sure it’s the one you want to delete. Enter ls test* to view files that match the word “test” and any other characters. The “*” character is called a “wildcard” and it means any characters here.

To get rid of files you use the “rm” command. Enter rm Testfile to delete the file called “Testfile” (with the uppercase “t”). Enter ls –l and you’ll find it’s gone. Where is it? It’s not in the Trash or Recycle Bin, like on a Mac or Windows PC. It’s deleted completely and cannot be recovered. Bear this in mind and always think before deleting files.

We see that “ls test*” matches two files: “test” and “testfile”, but not the file called “file”. That’s because it didn’t match the “test” part of “test*”. Check carefully over groups of files you want to remove (remember you can’t recover them) and replace the “ls” with “rm”. Enter rm test* to remove both files. Finally enter rm file to get rid of the confusing file.

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Create and Remove Directories Creating, moving and deleting directories isn’t as easy in Unix as it is with a desktop interface. You need to tell Unix to move the directories inside other directories, a process known as recursion. Sounds complex, but with these simple commands you’ll quickly get the hang of it. MANAGING FILES AND DIRECTORIES

Now that you know how to create files, you’ll want to learn how to make directories, which are the same thing as folders, as well as move items around. If you are more used to working with a desktop interface, this can take a bit of getting used to.

STEP 1

Enter ls to quickly view all the directories currently in in the home location. Directories are created using the “mkdir” command (make directory). Enter mkdir testdir to create a new directory in your home directory. Enter ls again to see it.

STEP 2

The “mkdir” command is different to touch, in that it doesn’t update the timestamp if you use it with a directory that already exists. Enter mkdir testdir again and you’ll get the error “mkdir: cannot create directory ‘testdir: File exists”.

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STEP 3

Like touch, you can create multiple directories at once with the mkdir command. Enter mkdir testdir2 testdir3 and enter ls. You’ll now find several directories called testdir. Also, like files, you should know this means you can’t (and really shouldn’t) create directories with spaces. As with files, use an underscore (“_”) character instead of a space.

STEP 4

You can create directories inside of each other using the directory path. Enter mkdir Documents/photos to create a new directory called “photos” inside your documents directory. The directory has to already exist, though, try to enter mkdir articles/ reports and you’ll get an error because there is no articles directory.

Create and Remove Directories

To create a directory path you need to pass in the “p” option to mkdir (which stands for “parents”). Options, if you remember, come after the command and start with a ‘-’. So enter mkdir -p articles/reports. Enter ls to view the articles directory, or “ls articles” to view the reports directory sitting inside.

STEP 5

Now you’re starting to get a bit more advanced, we’re going to just reiterate something. In Unix the command structure is always: command, option and argument, in that order. The command is the function, next are the options (typically single letters starting with “-”), and finally the argument (often a file, or directory structure). It’s always command, option, argument. Drill it into your head!

STEP 6

GETTING RID OF DIRECTORIES

Deleting directories is pretty easy in Unix, and like files this is a problem. It’s too easy to delete entire directories containing files, and these are instantly removed, not sent to a trash directory. Tread carefully. We’re going to remove one of the directories we created earlier using the “rmdir” command. Enter ls to view the files and directories in the current directory. We’ll start by getting rid of one of the test directories. Enter rmdir testdir3 and ls again to confirm the directory has been removed.

To delete a directory containing files or other directories, you return to the “rm” command used to remove files, only now we need to use the “-R” option (which stands for “recursive”.) Using “rm –R” removes all the files and directories to whatever you point it at. Enter rm -R articles to remove the articles directory.

Now we’ll try to get rid of the articles directory (containing the reports directory). Enter rmdir articles and press return. You’ll get an error saying “rmdir: failed to remove ‘articles’: Directory not empty”. This is a puzzler; the rmdir command only removes directories that having nothing in them (no files or other directories).

As with multiple files, you can delete multiple directories inside the same directory using the “rm” command with the wildcard character (*). This should be done with care though so use the -I option (which stands for “interactive”). This will prompt you before each deletion. Enter rm -Ri test* and press Y and return to each prompt. It’s a good idea to use the -i option whenever using the rm command.

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Copying, Moving and Renaming files Copying, moving and renaming files is essentially the same thing in Unix. Renaming a file is just moving it from one name to another, and copying it is moving it without deleting the original. It may seem a bit confusing at first, but these commands are the ones you need to know. USING THE MOVE COMMAND

Knowing how to move files is an essential part of learning Unix. Once you know how to move files and directories around you can start to organise your Raspberry Pi and place items where they are required.

STEP 1

Before we can move anything around, we need to have a few test items in our home directory. Enter touch testfile and mkdir testdir to create a test file and test directory in your home directory. Enter ls to check that they are both present.

STEP 2

Files and directories are moved using the “mv” command. This is different to commands we’ve looked at so far because it has two arguments (remember Unix command line is command, option, argument). The first argument is source (the file or directory to be moved); the second is the destination.

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STEP 3

Enter mv testfile testdir and press return to move the testfile document into the testdir directory. Enter ls to see that it’s no longer in the home directory, and ls testdir to see the testfile now sitting in the testdir directory. Now enter mkdir newparent to create a new directory.

STEP 4

Directories with files are moved in the same way. Enter mv testdir newparent to move the testdir directory inside the newparent directory. Let’s move into the directory to find the file. Enter cd /newparent/testdir and enter ls to view the testfile sitting inside the directory.

Copying, Moving and Renaming files

Files and directories can be moved up using the double dot (“..”) as an argument. Enter ls –la to view your testfile and the single and double dot files. The single dot is the current directory and the double dot is the parent directory. Enter mv testfile .. to move the testfile up into the newparent directory. Enter cd .. to move up to the parent directory.

STEP 5

You can also move files using longer paths. Enter cd ~ to return to the home directory and mv newparent/testfile newparent/testdir/testfile to move the testfile from its current location back inside the testdir directory. Enter ls newparent/testdir to view the file back in its current directory.

STEP 6

RENAMING FILES AND DIRECTORIES The mv command isn’t used just to move files; it also serves the purpose of renaming files (effectively it moves it from its old name to a new name). Let’s see how to use mv to rename items. Let’s start by making a new test file called “names”. Enter touch testfile and then ls to make sure the testfile is present. We’re going to turn this into a file that contains the names of some people. So let’s call it something more appropriate, like “names”.

You can rename directories inside other directories using paths. Let’s rename the testdir directory, which is now inside the people directory. Enter mv names/testdir names/ friends. Now enter mv names people/friends to move the names file inside the friends directory.

Enter mv testfile names and ls. Now we can see the new “names” file in our directory. The mv command can also be used to rename directories. We should still have our newparent directory in our home directory. Enter mv newparent people to rename the newparent directory. Enter ls to view it.

It is easy to overwrite files using the mv command, so if you have files with the same name use the “-n” option, which stands for “no overwrite”. Enter touch testfile to create a new file and mv -n testfile people/friends. There’s no error report though, enter ls and you’ll find testfile still there.

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Using the Man Pages Unix comes with man (manual) pages that explain each command and show you all the options you can use. Once you get the hang of reading man pages, you’ll be able to find and do just about anything in Unix. WHAT’S UP, MAN?

You’ve learnt some pretty cool stuff about commands, options and arguments, so now is a great time to start looking at the built-in help tool known as ‘man’ (short for manual). With man you can get information about the Unix commands.

STEP 1

Unix has a built-in manual, known as man for short. With the man command you can get information on all the Unix commands we’ve talked about. Just enter man and the name of the command you want to learn more about. Start by entering man ls in the command line.

STEP 3

Most commands are pretty easy to figure out how to use, so what you spend most of the time in the man pages is looking under the Description. Here you will see all the options and the letters used to activate them. Most man pages are longer than a single page, so press any key, such as the space bar, to move to the next page of content.

STEP 2

The man pages are a bit more detailed than you might be used to. First you have a name, which tells you what the command is called; in this case “list directory contents” and then the synopsis shows you how it works. In this case: “ls [OPTION].. [FILE..]”. So you enter ls followed by options (such as -la) and the file or directory to list.

STEP 4

Press the H key while looking at a man page to view the commands you can use to control the view. This is called the Summary of Less Commands (the less command is something we’ll come to when we look at editing text). For now realise that you can move back and forward with Z and W. Press Q to quit this help screen and return to the man page.

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Using the Man Pages

Scroll to the bottom of the man page to discover more information. Typically you will find the author’s name and information on reporting bugs, including web links that can be useful for more information. Press Q to exit the man page and return to the command line.

STEP 5

The man command can be used for just about every command you use in Unix. You can even enter man man to get information on using the man tool. From now on, whenever you come across a new command in this book, such as “nano” or “chmod”, take time to enter man nano or man chmod and read the instructions.

STEP 6

USING MAN OPTIONS

Because man doesn’t change anything, like mv or mkdir, it is tempting not to see it as a command. But it is, and like all other commands it has options. These can be very handy to learn. Entering man man enables you to view some of the options, but sometimes you’ll just want a quick overview. Fortunately man has a built-in help option that quickly lists the options. Press Q if you’re in a man page and enter man –h at the command line.

One of the most powerful man options is the -k option, which is for “apropos”. This enables you to search a wider range of man pages than the exact command. Enter man -k directory to view all of the man pages relating to directories “(man -k directory | less” to view one page at a time). Here you’ll find commands like “ls”, “mkdir” and “cd” along with their description.

If you’re fast you may have noticed the start of the text flew up off the page. This is because the “man –h” option doesn’t use the less command by default (less is what enables you to move down text one screen at a time). We’ll look into pipes (“|”) later on, but for now just use “man -h | less” to read long text one page at a time.

Entering the man page for all the commands you come across can be a little long-winded, although ultimately productive. If you simply want to know what a command does you can read just the description using the “whatis” command. Enter whatis pwd to read the description of the “pwd” command (“print name of current/ working directory”).

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Editing Text Files Unix is formed by hundreds of text files, and you’ll often end up creating more text files to contain your programs and scripts (short programs that automatically perform tasks). You can use programs to edit text, but it’s also possible to perform quick edits right inside Unix. TEXT EDITING

Files in Unix are all constructed of text and code, which is text. Often you’ll be asked to open a file, and insert or adjust the text inside. As you get more advanced, you’ll be creating and editing configuration files and your own programs.

STEP 1

You’re probably used to editing files in the LDXE environment using a text editor, such as Text Edit. If you’re in the command line, enter startx to enter the desktop. Open Text Edit (Menus > Accessories > Text Editor). We’ve written out a Haiku poem and saved it using File > Save As. Enter the name Haiku and choose the Documents directory. Click Save.

STEP 2

We’re going to back out of the desktop environment and into the command line. We just want you to see that the text documents created in Text Edit contain just text, and show you the relationship between files in the desktop and command line. Open LXterminal and enter pkill x to close the desktop environment and return to the command line.

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STEP 3

Enter clear to remove the text from the screen and “ls –l” Documents to view the files in your Documents directory. You will see the Haiku file you created in text edit. Note the number to the right of “pi”. If you entered the document with the same text as us, it should read 83. This is the exact amount of characters in our poem.

STEP 4

The cat command can be used to view the contents of a text file in Unix. Enter cat Documents/Haiku to view the text inside the Haiku file. Cat is short for “concatenate”, and was designed to list the text from various files together, and you can use several files as arguments for cat, but most people just use it to list the contents of a single file.

Editing Text Files

What if you want to edit a file? For that we turn to a text editor that works from the command line. There are two main text editors available: Vim and nano. We believe nano is best to start with, so enter nano Documents/Haiku. The command line vanishes to reveal the GNU nano text editor.

STEP 5

Text is edited in nano in much the same way as other word processors, although it is far more limited in scope. Use the arrow keys to move to the end of the text and press return to add a couple of lines. Now enter some more text and it will be added to the document.

STEP 6

SAVING EDITED FILES

Because nano is such an old program, many of its conventions are odd. You might find saving and closing the app tricky at first. Don’t worry; follow these steps to get the hang of it. You don’t save the text using the traditional Control+S function found in programs worldwide; instead you WriteOut a file using a Control+O shortcut. Press Control+O and a bar appears at the bottom of the screen with File Name to Write and the document path.

STEP 1

Enter cat Documents/Haiku to view the updated text. Also enter ls -l Documents to view the updated Haiku file in the Documents directory. Check the file size and you’ll see it has increased by the same amount of letters (including returns at the end of lines) you entered into the Haiku document. Remember that one byte equals one letter in a document.

STEP 3

You should be aware that you can use nano to create empty text documents. Type nano Haiku in the home directory and you’ll create a blank document called “Haiku” instead of opening your document. If you ever try to open a document and get blank text, the chances are you have got the directory path correct.

STEP 4

By default the file name should be correct in the File Name To Write section and all you need to do is check it and press return. We found this strangely challenging at first, and often reached for the Y key to confirm the save. Once it has saved you quit nano by pressing Control+X (not the usual Control+Q command).

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Getting to Know Users You might think you’re the only person using your Raspberry Pi, but there are several different users and even groups of users. Your main account is normally called “Pi”, and there is an account above it called “root”, which is more powerful. You can also create users and groups. WHAT IS A USER?

An important part of using Unix is the concept of users and understanding which user you are, and which group you belong to. Like all modern computers, you can have multiple user accounts, and each has different types of access.

STEP 1

The first thing you need to do is get a concept of which user you are. Enter whoami into the command line and press return. It should say “pi” (unless you set up your account name differently during setup). The “whoami” command might seem a bit simplistic, but it comes in very handy sometimes.

STEP 2

There are times when you’ll be doing something in Unix and get an error with “Permission denied”; typically when you try to create, edit or execute (run) a file or directory outside of your area of privilege. If you want to see this, enter mkdir /testdir. Attempting to create a new directory in your root directory isn’t allowed.

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STEP 3

To do this you’ll need to use a command called sudo. It’s thought to stand for super do, although it means perform this command as the user above me, which is usually the root user. You’ll come across sudo a lot in Unix, so let’s create a second account to really get the hang of it. Enter sudo useradd -m lucy (or pick your name). Enter your password.

STEP 4

Now add a password for the new account. Enter sudo passwd lucy and enter a short password. Retype the same password and you’ll now have two accounts on your Raspberry Pi. Now enter ls -l /home to view the home directories for both users. Notice that the lucy directory lists lucy as the owner and group; and pi directory is belongs to pi.

Getting to Know Users

Let’s try switching to our new account. Enter su lucy and enter the password you just created for that account. Notice that the command line now says “lucy@raspberrypi” but the working directory is “still /home/pi” (check this using “pwd”). Enter whoami to confirm that you are now the new user.

STEP 5

We’ll look at permissions in the next tutorial, but for now try to create a file as before. Enter touch testfile to create a file. It will say “touch: cannot touch ‘testfile’: Permission denied”. This is because your new user account doesn’t have the right to create files in the /home/pi directory. Enter su pi to switch back to your pi account.

STEP 6

GETTING SUDO

We now have two accounts on our Raspberry Pi: lucy and pi. The lucy account can edit files in /home/lucy and the pi account can edit files in /home/pi. But there’s also a third account, called “root”, that sits above both lucy and pi. It can edit files anywhere. The root account is all-powerful. It is possible, but not recommended, to switch to the root account, although you’ll need to give it a password first (using “sudo passwd root”). Then just type “su” to switch to root. Please don’t do this though: knowledge is a good thing but it’s safer and wiser to use sudo instead.

STEP 1

It’s rare that you use sudo to substitute another user. If you don’t specify a user using the “-“u option with a username it defaults to the root account, as if you’d typed “sudo -u root”. Enter sudo touch /home/lucy/anothertestfile to create a file in the lucy directory while still using the pi account.

STEP 3

This step is optional. Only the pi user can use sudo. If we want to give the lucy account sudo privileges, it needs to be added to the sudoers file. Enter sudo visudo to view the sudoers file. Add lucy ALL=(ALL) NOPASSWD: ALL to the last line and use Control+O to output the file. Remove the “.tmp” that is added to the file name as a security measure. Note that most accounts are not added to the sudoers file as a matter of course.

STEP 4

Most people think sudo stands for “super user”, but it stands for “substitute user do”. It enables you to perform a command as another user. Enter sudo -u lucy touch /home/ lucy/test to create a file inside the lucy home directory. You won’t get an error because the lucy user has permission to edit that directory.

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Ownership and Permissions Once you’ve got the hang of users, you’ll need to learn about ownership and permissions. Different users have different areas of ownership, and can do different things with each file. Permissions in Unix is quite arcane, but our guide will have you reading them in no time. OWNER AND PRIVILEGE

An important part of using Unix is the concept of users and who owns files, and who has privilege rights. Like all modern computers you can have multiple user accounts, and each has different types of access. You need to know this information to manage files.

STEP 1

If you followed the previous tutorial you should now have two accounts on your Rasbperry Pi. One called “pi” and the other with a name (lucy in our case). An essential aspect of Unix is the idea of file and directory ownership; who owns, and has access to what. We need a test file; enter touch testfile.

STEP 3

The first letter in the permissions also indicates a directory or file. Notice that all the other files start with a ‘d’ and our textfile.txt file starts with a ‘-’. That’s what the first letter means. It’s either a ‘d’, in which case it’s a directory, or a ‘-’, in which case it’s not; it’s a file. Enter ls -l testfile.txt to view the permissions for just this file.

STEP 2

Now enter ls –l and let’s have a good look at the default permissions file. Our testfile.txt files starts with the text “-rw-r--r—“. Start with the first letter, which is a dash ‘-’. All the other items in our home directory are directories. You can tell because they are blue, and our testfile.txt file is white.

STEP 4

The next nine letters of the permissions are known as “alpha notation” because they let you know the permissions using letters. Each permission is either on, in which case you see a letter, or it is off, in which case you see a dash. The letter doesn’t change for each place. So the first permission - the second letter after the directory one - is either an ‘r’ or a ‘-’. It’s never any other letter.

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Ownership and Permissions

The ‘r’ means that particular permission is read and it’s set to On. The nine letters here are divided into three groups of three letters: r, w, x. They stand for read, write and execute (run). Read means the file can be viewed (using cat or nano); w means the file can be edited or moved, and x means the file - typically a script or program - can be run.

STEP 5

The presence of r, w, or x means that this aspect is possible, a dash means it isn’t. Our testfile.txt has no x letter; so if it were a script it wouldn’t run. So why are there so many letters? Why not just three; read, write and execute? The three blocks of three letters are for different sets of people: user, group and other.

STEP 6

CHANGING PERMISSIONS

Now that you know how groups of permissions work, it’s time to look at how to change them. The first block of three is the most important. This is the user who owns the file (typically pi); the second is for other people in the same group as the user, and the third is for other people on the system. Permissions are changed using the chmod (change file mode bit) command. Enter man chmod to look at the manual.

STEP 1

Turning everything on is probably overkill, so you need to target each group. Do this by putting commas between each mode option. Enter chmod u=rwx,g=rw,o=r testfile.txt to give users read, write and execute privileges, user read and write and other just read. Enter ls –l to see your handiwork.

STEP 3

Alpha notation is fine, but many Unix experts use octal notation instead. This is a three-digit number that represents permissions. This is the formula: read=4, write=2 and execute=1 and you add them up for each group. So if a group is read, write and execute it’s 7; if it’s read and write it’s 6, or if it’s just execute it’s 1. A popular option is 755. Enter chmod 755 testfile.txt to change the file using octal notation.

STEP 4

The chmod command is one of the tricker ones to understand. There are two ways you can adjust permissions; the first is using chmod with an option to target one of the three groups: owner, group, other. For these you use u, g or o followed by = and the letters or dashes you want. So enter chmod ugo=rx testfile.txt to make all three groups read, write and execute.

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Useful System and Disk Commands By now you’ll pretty much have Unix working for you, but there’s a lot more to learn. While we can’t show you everything on your Raspberry Pi, learning these Unix commands will put you in a much better position to start programming. LOTS OF UNIX

Unix is a huge and versatile command line language, and there are hundreds of commands you can learn and use. Here are some that will help you get more from your Raspberry Pi.

STEP 1

The Raspberry Pi is a great little computer, so let’s start by getting some information. Enter cat /proc/cpuinfo to view some details on your Raspberry Pi processors. If you have a Raspberry Pi 3 you will see four processors, along with the model name and other info.

STEP 2 Remember that cat is used to list the contents of a text file, which is what cpuinfo is. There are other text files with system info available. Try “cat / proc/meminfo” to get information about your memory, “cat /proc/ partitions” for information about your SD card, and “cat /proc/ version” shows which version of Raspberry Pi you are using.

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STEP 3

Enter uname to view the name of the operating system’s kernel (the bit that sits between the interface and hardware). You might wonder why it says Linux and not Unix or Raspbian? That’s because Raspbian OS is a Linux-based operating system, and Linux itself is based on GNU (a recursive acronym that stands for GNU is Not Unix).

STEP 4

Enter uname –a to view some more detailed information. Here you’ll see the kernel name, hostname and kernal version (3.18.7-v7 on ours). If you have a Raspberry Pi 2 you’ll see SMP (symetric multiprocessing), followed by the system date, CPU architecture and operating system (GNU/Linux).

Useful System and Disk Commands

Enter vcgencmd measure_temp to view the current operating system temperature of your Raspberry Pi. Enter vcgencmd get_mem arm to view the RAM available, and vcgencmd get_mem gpu to view the memory available to the graphics chip. Finally try ls usb to view a list of attached USB devices.

STEP 5

One command you might be wondering about is how to switch off or restart your Raspberry Pi from the command line. Don’t just hit the power switch. Enter sudo showdown –h now to shut down the Raspberry Pi (the “-h” option stands for “halt”), or enter sudo shutdown –r now to restart your Raspberry Pi.

STEP 6

DISK COMMANDS

Learn the two commands that enable you to view your disk space and the files on it: df (disk free space) and du (disk usage). With these two commands you can view the file usage on your SD card. Start by entering df in the command line. It returns a list of the volumes contained on your SD card. You might be wondering what a volume is. It’s best to think of your SD card as the drive. This contains partitions, which is where you split one drive to act like two or more drives. And each partition can contain volumes, which are storage spaces.

Now enter du. You should see lots of text fly up the screen. This is the disk usage for the files contained in your home directory and their sub-directories. As with df, it is better to use du with the “-h” option to humanise the output. If you want to slow down the output, you’ll also need to pipe it through less. Enter df -h | less to view the files and their respective usage one page at a time.

Enter df –h to get the list in human readable form. The first two lines should read “rootfs” and “/dev/root” and have matching Size, Used, Avail and Use% listings. This is the main drive, and is an indication of how much space you have used, and have free, on your Raspbian OS. The other volumes are for booting and initialising devices (you can ignore these for now).

You don’t typically enter du on its own; most of the time you want to view the disk usage of a specific directory. Enter du -h python_games to view how much space the python_games directory (installed alongside Raspbian) takes up. It should be 1.8M. If you want a more comprehensive breakdown of the files contained, use the “-a” option (all). Enter du -ha python_games to view all the files contained and their disk usage.

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Managing Programs and Processes The more you use Unix, the more likely you are to run into crashed programs, faulty processes and problematic errors. Most of these can be determined and fixed by learning to manage programs and processes. PROGRAMS AND PROCESSES

If you’ve come from a desktop computing environment, you’ll be used to the idea of program that you open and quit using the desktop interface. Programs are managed by the operating system, which manages programs and processes. But what on earth is a process?

STEP 1

As you get into Linux you’ll start to hear more about processes and another thing called the “kernel”. The kernel sits beneath the software and hardware. It passes instructions to the hardware running processes, which takes up memory, and when the process is finished it closes it and reclaims the memory.

STEP 3

If you type in “ps” on its own you don’t see much. You should see two items: bash and ps. Bash (Bourne Again Shell) is the command line environment you are typing in, and ps is the command you just entered. If that seems a little light, that’s because it is. These are just the processes owned by the user and are running in the foreground.

STEP 4

STEP 2

You’re probably used to thinking in terms of programs and most OS’s tend to keep processes out of sight. In Linux on the other hand, you’re right in at the deep end. A process is like a program, only it’s a single task running on your computer. Programs as you know them, may be a single process, or multiple processes working together. In Linux, you should learn to manage processes. This is done using the “ps” (process status) command.

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If you want to see processes used by other users (including those started by root) enter ps –a. The option stands for all users. This still isn’t everything though because it doesn’t include background processes. For this you can enter either “ps –A” or “ps –e”. This will show you every process on the system including the background processes. You may need to pipe it through less using “ps -e | less”.

Managing Programs and Processes

The ps command is one of the oldest known, and it has a lot of legacy. Because of this, it also has alternative options that can be used without the dash at the start. The most common way to use ps is to enter ps aux. Piping this command through less is the best way to go about using ps. Enter ps aux | less to view your processes.

STEP 5

The “ps aux” command displays the processes in columns. The first is the User followed by the Process ID (PID), then we see the percentage of CPU and memory.

STEP 6

VIEWING AND QUITTING PROCESSES

Now that you’ve got a handle on processes, you need to know what to do with them. You can view processes running in real-time, and quit ones that you no longer need, or those that are problematic. While ps is a great tool for checking all the processes on your Raspberry Pi, sometimes you need to view them in real-time. In particular you may want to check the CPU and memory usage of processes and see if any process is hogging all your computer’s resources. Use “top” to do this.

Now that you’ve got an idea of what processes are, how do you go about stopping them? Some processes run in the foreground until you quit them. Enter ping www.google.com and you’ll start a ping process continuously contacting Google. This sort of process runs until you press Control+C.

Top fills the display with processes and it fits as many as it can on one screen. These run in real-time so as you watch, the display items will move up and down according to their usage. You can interact with top as it is running: use < and > to change the sort column. Press H to view a help page with all the commands you can use.

Processes are stopped using the kill command. Enter sleep 100 & to create a dummy process. Enter pgrep sleep to find its PID number (on ours it is 2192). Now enter kill 2192 and the sleep process will be stopped. You can also use pkill sleep if you’re sure you know the process name.

STEP 1

STEP 2


STEP 3

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Input, Output and Pipes You’re getting the hang of things now, and this is where Unix gets serious. The ability to change input, output and pipe commands from one to another is why Unix is much more powerful than any desktop interface. INPUT AND OUTPUT

Everything on a computer is about input and output. You input things into the computer (press keys, move the mouse) and it makes calculations and outputs things (changes the display, makes a noise, for example). In Linux you really get to learn about it.

STEP 1

When you enter commands into Linux (in the command line), you are using standard input and output. This is so obvious that most people don’t even think about it. You enter commands using the keyboard (that’s input) and it responds to the screen (output). This is the regular way of doing it, which is why it’s “standard input and output” (often called “stdin” and “stdout” for short).

STEP 3

You can change the standard output to something else using the “>” character after your command. If we wanted to see all the items in the python_games directory we could use “ls -l python_games”. Using “ls -l python_games > games.txt” outputs the list of items to a new text file called “games.txt”.

STEP 4

The games.txt file now contains the output from the ls command. You can check it using “nano games.txt”. It’s an editable text file containing all the permissions, user and file size information and the names of the files. The output from the ls -l command, normally displayed on the screen, was instead sent to this file. Press Control+X to quit nano.

STEP 2

As far as the computer is concerned, input and output can be to and from a whole range of different sources that you might never even think about. A program can get input from other programs, from files stored on the hard drive and a whole host of other areas. It outputs back to the display line, but also to files, other programs and even other commands.

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Input, Output and Pipes

So > enables you to output to files, but you can also get input from a file. Make a new directory called music (“mkdir music”) and switch to it (“cd music”). Enter nano bands.txt to create a new text file. Enter some band names and press Control+O to output the file. Press Control+X to quit nano.

STEP 5

We’re going to use this text file as input to the sort command. Enter sort < bands.txt and the content from the text file is used as input to sort. Because the output isn’t specified, it uses the standard output (the screen) but you use input and output together. Enter sort < bands.txt > bands_sorted.txt to create a new file with the band names in order to switch back to your pi account.

STEP 6

USING PIPES

As well as directing input and output to and from files, you can send the output from one command directly into another. This is known as piping, and uses the pipe character “|”. As you start to get more advanced in Linux, you begin to create more powerful commands, and one way you do this is by using the pipe character (“|”). Take some time to find this character if you haven’t already: it usually sits above or to the left of the Return key on most keyboards.

You can pipe commands multiple times. Enter cat bands.txt | sort | grep The* to get the bands starting with “The” in alphabetical order. The output of the text from the bands.txt document is passed into sort, and the output from sort is passed into grep which filters out the bands starting with “The”. These bands form the output.

We’ve used the pipe a few times in the book (“ps aux | less”), but you might not have understood what’s actually happening. Enter cat bands.txt | wc. The output from the cat command (the text inside the document) isn’t displayed on the screen, instead it is piped into the wc (word count) function. This then tells us how many lines, words and characters are in the document.

You can combine pipes with input and output to create complex expressions. You can also use >> to append outputted data to a file that already exists. Enter cat bands.txt | wc >> bands.txt. This takes the output from the bands.txt file and pipes it into the wc (word count) function. The output from wc is appended to the end of the bands.txt file. Enter cat bands.txt to view it.

STEP 1

STEP 2


STEP 3

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How to Customise Unix We’re almost done with Unix, and about to move on to learning the basics of programming. Before we go any further, we’re going to look at how to customise the Unix system space. Personalising Unix makes it a much friendlier place in which to work. IT’S YOUR UNIX

One of the joys of working from the command line is that you can customise it to your heart’s content. Discovering how to customise the command line also teaches you a bit about how your Raspberry Pi hardware gets going at startup, so it’s a lesson worth learning.

STEP 1

One of the reasons for getting a Raspberry Pi is to learn more about how a computer works. One question is, how does it start? How does the Raspberry Pi know what to do when you hit the power switch - known as booting the computer, because you kick it into action. What happens when you put your boot up the Raspberry Pi’s bottom?

STEP 3

You can find the bootloader using the find command: “sudo find / -name bootcode.bin –print”. It is in /boot/bootcode.bin. Don’t ever edit this file; just know it exists. The bootcode.bin file then starts another file in the /boot directory called “start.elf”. This is known as the “third stage bootloader” and this is where the action really happens.

STEP 4

You can’t view the start.elf file, just know that it is responsible for launching the files you can view and edit. One of these is /boot/config.txt. View the contents using “sudo cat /boot/config. txt | less”. Occasionally you may come across a feature that requires you to edit the config.txt file. Make a backup first though using “sudo cp /boot/ config.txt /boot/config_backup.txt”. Enter sudo nano /boot/config.txt to edit the contents of the file.

STEP 2

When you power up a Raspberry Pi, it fires up the ARM processor and GPU (Graphics Processing Unit). Together these form the SoC (System on Chip). This is the big chip in the middle. Part of the SoC is a small ROM known as the “first stage bootloader”. This piece of ROM searches the SD card for a file known as the “second stage bootloader”.

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How to Customise Unix

The config.txt file has a simple property=value structure, making it easy to read. Most of the text here starts with a #, which comments out the command. This turns that line into a comment, meaning that command is skipped over. We’re going to change to monitor resolution. Scroll down to “#hdmi-group=1” and remove the #. Now do the same for the line below (“hdmi_mode=4”). Change “hdmi_mode=4” to “hdmi_mode=2”. Press Control+O to save the file and Control+X to exit.

STEP 5

Enter sudo reboot to restart your Pi in a much lower resolution. Use “sudo nano/boot/config.txt” and replace the hash (#) symbols in front of the “hdmi_group=1” and “hdmi_mode=2” settings to return to normal (find the # symbol using right-alt and 3). Save, exit and use “sudo reboot” to restart in your usual resolution. A list of config.txt edits is found here: https://www.raspberrypi.org/documentation/ configuration/config-txt.md.

STEP 6

EDITING .BASHRC

Another file the bootloader instigates is a hidden file in your home folder called .bashrc. This enables you to customise your bash (the command line environment). You can find the .bashrc file using “ls –lah” and edit it using nano. Like the config.txt file it’s best to start by making a backup. Enter cp .bashrc .bashrc_backup then nano .bashrc (you don’t need sudo as it’s in your home folder). Like the config.txt file you’ll see a lot of options that are commented out with the hash symbol.

STEP 1

The new alias won’t work until you restart the command line. You could use “sudo reboot”, but in this case it’s faster to enter source .bashrc. This reloads the .bashrc file. Now enter ll and you’ll get the directory contents in list format, just as if you’d entered ls –l. It’s a handy shortcut that many Unix users use.

STEP 3

While config.txt affects the physical settings of your hardware, .bashrc is much more about the settings of your command line. Some handy aliases (shortcuts for common commands) are commented out. Scroll down to # some more aliases and remove the # before #alias ll=’ls -l’. Save and quit.

STEP 2

There are a lot of other alias options. Reopen .bashrc (nano .bashrc) and scroll down to remove the hash in front of the other alias options and test them out. You can also add your own. Enter alias up=’cd ..’ or alias desk=’cd ~/Desktop/. Now when you enter up you’ll go to the directory above, or desk takes you to your desktop directory.

STEP 4



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FUZE and Introduction to Coding INDEX

FUZE and Introduction to Coding The Raspberry Pi is the powerhouse for many projects but one in particular stands head and shoulders above the rest, the FUZE Project. The FUZE is a learning environment for the Raspberry Pi that’s used in schools across the UK. It combines imagination, engineering and education in a cleverly designed retro-themed keyboard case. We’ll look at the models available and how to get up and running with the FUZE. The FUZE comes with its own programming language, FUZE BASIC. This allows you to create simple routines, games, complex algorithms and even interact with robots and other electronics. We’ll also look at the popular Scratch highlevel programming language, and dig a little into the latest version of Python.


98 Introducing the FUZE Project

122 Getting Started with Scratch

100 Setting up the FUZE

124 Creating Scripts in Scratch

102 Getting Started with FUZE BASIC

126 Interaction in Scratch


128 Using Sprites in Scratch


130 Sensing and Broadcast

108 Coding with FUZE BASIC Part3

132 Creating and Using Variables

110 Using a Breadboard

134 Getting to Know Python

112 Using the FUZE IO Board

136 Start Using Python

114 Using a Robot Arm with FUZE BASIC

138 Working with Variables


140 Creating Functions in Python


142 Conditions and Loops

120 Introducing Scratch

144 Python Graphics


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Introducing the FUZE Project The FUZE Project is a learning environment that’s built around the Raspberry Pi and a custom programming language based on BASIC. The FUZE Workstation is the hardware side of the project, incorporating a Raspberry Pi inside a stunning retro-themed case, complete with a full-sized keyboard, IO board and connectivity. The software side is FUZE BASIC, available for both Windows and as a boot image for Raspberry Pi models 2 and 3. The FUZE Workstation itself, styled on a BBC Micro Model B from the ‘80s, constructed with a metal body and high quality keyboard complete with programmable red coloured F-keys. Note the holes at the top edges: these are compatible with many popular plastic building blocks and electronic construction kits.

The Rear IO back plate is where you plug in your power, connection to a monitor, mouse, SD card, audio and any USB devices you want to include. From left to right, across the backplate, there’s an on/off switch, a power port, a bank of four USB ports, the Ethernet port, SD card slot and HDMI port. You can remove the four corner screws of the backplate to gain access to the Raspberry Pi, USB hub and cables inside the workstation if needed.

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Inside the FUZE workstation is the beating heart of the project, a Raspberry Pi 3. It’s connected to the FUZE IO board via the 40-pin GPIO pins with a ribbon cable, with the other connections branching from it: HDMI, power, SD Card and USB. The USB ports have been routed to a powered USB hub, attached to the rear of the workstation, providing the user with four USB ports accessible through the rear IO back plate; there’s an Ethernet port too.

The FUZE IO board, located in the wide slot at the top of the workstation, is the connection to extended hardware. With it you can connect, program and use sensors, LEDs, robotics and all manner of amazing electronic projects.

Introducing the FUZE Project

You also receive an electronics kit as part of the FUZE workstation, to help you get started on some of the projects the FUZE is designed to support. Within the kit you can find 24 coloured LEDs, 1 seven-segment LED, 1 light dependant resistor, 8 micro switches, 30 mixed specification resistors, 20 jumper cables and 60 jumper wires.

Complimenting the electronics project kit, the FUZE team also bundles an 840-socket solderless breadboard which you can use to wire up interesting projects and use FUZE BASIC together with the Raspberry Pi and the FUZE IO board to control the components from the electronics kit. In case you’re wondering why it’s called a breadboard, it’s because in the early days of electronics users would use a bread board for the base of their projects.

Alongside the other components with the FUZE workstation, you also get either a wired USB or wireless (batteries are included if necessary) mouse and ‘FUZE’ logo mouse mat.

The kit comes with two ring-bound books containing project ideas for the electronics kit and a programmer’s reference guide for FUZE BASIC. If you’ve purchased the FUZE kit, then it’s certainly worth your while reading through this book and familiarising yourself with how everything works.

Depending on which FUZE workstation kit you’ve purchased, you could also have a robot arm that requires building, along with four D-sized batteries, a BBC micro:bit or even a Capacitive Touch kit. Needless to say, there’s plenty of project potential with the FUZE.



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Setting Up the FUZE Thankfully the FUZE Project comes with everything you need to get up and running; you just need to supply the monitor and an Ethernet cable to your network (or you can go Wi-Fi with the Raspberry Pi 3). Before you begin though, let’s see how to set up the workstation. LIGHT THE FUZE

Getting the FUZE up and running is as simple as plugging in a standard desktop computer; but it’s always worth running through the process for those who don’t know what to do.

STEP 1

Before you power up your FUZE, make sure that the provided SD card is inserted into the SD card slot to the rear IO backplate of the FUZE workstation. The chances are the SD card is already inserted but depending on how the FUZE was packaged, it may be in the electronics kit box.

STEP 2

Grab a spare monitor or if your existing monitor (or TV) can support more than one HDMI connection even better. The FUZE comes with a quality HDMI cable, remove it from its bag and connect one end to the HDMI port on the rear IO backplate of the FUZE and the other to the rear of the monitor or TV.

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STEP 3

For now, use the Ethernet port, LAN cable, for the FUZE’s connection to the home network and ultimately the outside world. You can set up the Wi-Fi but it’s always easier to establish a wired connection first if possible. Connect the Ethernet cable to rear IO backplate of the FUZE.

STEP 4

Next, open up the box containing the mouse and plug it into one of the USB ports on the rear IO of the FUZE workstation backplate.

Creating Scripts in Scratch

Now open the box containing the power pack and plug it into the power point at the wall and finally to the FUZE workstation itself. The FUZE will power up immediately and start to boot into the custom FUZE Raspbian OS on the SD card.

If you want the Wi-Fi to be the active network connection, look to the bottom right of the desktop for the two arrows (one pointing up, the other down). Click the arrows and the current Wi-Fi access points will be displayed. Connect to yours as you would normally. You can now unplug the Ethernet cable if you wish.

You may need to change the source of the monitor or TV’s input to the HDMI, or the numbered HDMI port that you’ve connected the FUZE to. Once the signal is found by the monitor it displays the FUZE desktop.

Beyond the different desktop presentation, the FUZE setup works exactly the same as any other Raspberry Pi Raspbian system. You can click the first F (the white F on a black background) to open the system menu detailing the available apps and programs. The second F launches FUZE BASIC, which we’ll look at in the next tutorial.

The first thing to notice is that it’s significantly different to that of the standard Raspberry Pi Raspbian interface. The launch panel and buttons are located along the bottom of the screen, as with a Windows-type setup, with a couple of icons on the desktop itself.

To ensure you’re running the latest software and programs, click on the F start button, followed by Accessories > Terminal. In the Terminal enter: sudo apt-get update && sudo apt-get upgrade and accept any changes and updates the system has to offer. This will update all your installed software and system files.

STEP 5

STEP 6

STEP7


STEP 8

STEP 9

STEP 10


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Getting Started with FUZE BASIC FUZE BASIC is a marvellous programming language to begin learning to code with. It greatly mimics the ’80s BASIC versions from the 8-bit machines of the time, such as the Commodore 64, ZX Spectrum and BBC Micro. BACK TO BASICS

Let’s begin our programming journey with FUZE BASIC, an environment where you can create anything, from simple scripts to complex games with graphics and sounds.

STEP 1

in the bottom right panel, the one that’s coloured white on a red background? Click it and you launch the FUZE BASIC, complete with a C64-style retro interface. You can also double-click the FUZE BASIC V3 icon on the desktop.

STEP 2

Don’t worry if you don’t have a FUZE Workstation. FUZE BASIC is available for Windows, the BBC micro:bit and the Raspberry Pi (since it’s already running on a RPi). Open a browser to www. fuze.co.uk/download-fuze.html and follow the download instructions for FUZE BASIC for Windows and the step-by-step instructions to install it on a Raspberry Pi.

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STEP 3

The retro style interface of FUZE BASIC has several themes that you can cycle through, depending on your taste. The default view is that of a Commodore 64 but if you want a different view press the Insert key to cycle through the available interfaces. You’ll no doubt recognise some of them, so find one you like.

STEP 4

The screen you’re looking at now is called Immediate Mode; pressing the Enter key will reveal a cursor where you can start to enter code. Try this: press Enter, then type: Hello everyone and press Enter again. The output on the screen will display whatever you’ve typed into the quotation marks.

Getting Started with FUZE BASIC

You can also Print the total output of several numbers from within the Immediate Mode. For example, try: print 10 + 20 + 30, and press Enter. The sum of the numbers you’ve entered will now be displayed on the screen, in this case the number 60. Try more numbers and even different mathematical symbols.

STEP 5

Before we get into variables and other such programming terms, let’s have a little play around with a quick listing to ask for user input. Enter this:

STEP 8

10 20 30 40

cls input “What is your name? “, n$ print print “Hello “; n$

Enter run to execute the code.

If you find the screen getting a little full, enter cls to clear the BASIC display. BASIC in Immediate Mode is also capable of storing variables, something which we’ll look at in more depth in the next tutorial. For now, try this and press Enter after each line:

STEP 6

A=10 Print a

If you’re old enough to recall BASIC from the early days of computing, you’ll no doubt remember that coding came with line numbers. FUZE BASIC works the same way. Whilst still in Immediate Mode, enter:

Dissecting the previous code, we have the command to clear the screen [CLS], then the Input command asking for user input and storing the input as the variable n$. The Print at line 30 puts a blank line on the screen, whilst the Print command at line 40 displays the message Hello and the contents of the variable n$.

STEP 9

STEP 7

10 print “Hello” 20 goto 10

Now enter run. The word Hello should now cycle down the screen. Press the Escape key to exit it.


There’s a lot you can do in Immediate Mode; however, to unleash the full potential of FUZE BASIC you’re best working in the Program Editor. To enter the Program Editor type in the command new to clear any programs already stored in memory and press the F2 key. As you can see, Program Editor looks significantly different to Immediate Mode.

STEP 10


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Coding with FUZE BASIC Part 1 Variables are used in programming to store and retrieve data from the computer’s memory. It’s a specified location in memory that can be referenced by the programmer at any point in the code, as long as it’s created and valid. LET THERE BE VARIABLES

We’ve already looked at assigning some variables in the previous tutorial so let’s extend that and see what else we can do with them.

STEP 1 each line:

Enter the Program Editor, by pressing the F2 key. Within the Program Editor enter the following, pressing Enter after

Let x=10 Print x

Now click on the Save button, along the top of the screen and save the program as ‘Variables1’. Click the OK button to return to the Editor and the Run button to execute the code.

STEP 3

Let x=10 Let y=20 Let z=30 Print x + y + z

Save as ‘Variables2’ and Run it. You now have the output of 60 on the screen, as you’ve assigned X, Y and Z with numerical values, and printed the total.

STEP 4 Let x=10 Let x=x-1 Print x

STEP 2

After clicking Run you drop back into Immediate Mode and the display will output the number 10. To break down this simple code, you’ve created the variable called X, and you’ve allocated the value 10 to it. The second line simply prints the current value of X – which is of course, 10.

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Press F2 to enter Editor mode and click on New. Now let’s expand on the simple code. Enter the following:

What if we wanted to change the value of a variable? Enter this listing:

To begin with X equalled 10 but the next line subtracts 1 making it 9, then prints the current value of X. Imagine this as lives in a game, starting with 10 lives, losing 1 and leaving 9 left.

Coding with FUZE BASIC Part 1

STEP 5

We can extend this further with more commands. Try this: Let x=10

Cycle Print x Let x=x-1 Repeat until x=0 Print “Blast Off!” End

The code from Step 7 introduced some new commands. First we clear the screen, then ask for user input and store it in the variable name $. Line 3 starts the conditional statement, if the user enters the name ‘Dave’ then the program will print HAL’s 2001 infamous lines. If another name is inputted, then it will print something else.

STEP 8

This creates a loop that will minus 1 from X until it reaches 0, then prints Blast Off!

STEP 9 STEP 6

Variables can do more than store numbers:

Input “Hello, what is your first name? “, f$ Print Input “Thanks, and what is your surname? “, s$ Cls Print “Hello “; f$; “ “; s$; “. How are you today?” End The variables f$ and s$ store input from the user, then printed it back to them on the same line.

STEP 7

Programs store all manner of information, retrieving it from memory in different ways:

cls Data “Monday”, “Tuesday”, “Wednesday” Data “Thursday”, “Friday”, “Saturday” Data “Sunday” Dim DaysOfWeek$(7) For DayNo = 1 TO 7 loop Read DaysOfWeek$(DayNo) Repeat For DayNo = 1 TO 7 loop Print “Day of the week number “; DayNo; Print “ is “; DaysOfWeek$(DayNo) Repeat End

Conditional statements allow you to make your program do different things depending on the user input. For example:

cls Input “Enter your name: “, name$ If name$=”Dave” then Print “I am sorry “; name$ Print “I am afraid I can’t do that” Else Print “That is not a problem “; name$ Endif End

The code from Step 9 is beginning to look quite complex, using the Data command to store constant data, creating a variable called DaysOfWeek using the Dim command and assigning it an indexed dimension (7). The code then Reads the stored Data, assigns it a variable dimension from 1 to 7 and prints the result.

STEP 10

Save as ‘HAL’ and Run.



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Coding with FUZE BASIC Part 2 Moving on from the previous FUZE BASIC tutorial, let’s expand everything you’ve done so far and see if we can apply it to something other than counting numbers or asking for someone’s name. In the grand tradition of BASIC programming, let’s create a text adventure. “PALE BULBOUS EYES STARE AT YOU…”

A text adventure game is an ideal genre to explore your BASIC skills in. There are variables, events, user input, counting and if you want, even a few graphics here and there to inject and use.

STEP 1

Enter the Program Editor and begin with a simple clear screen, as it’s always a good way to start. What we need to do is set some basic parameters first, so start with the number of lives a player has, for example 3. Cls Let lives=3

STEP 2

Now you can introduce the game and let the player know how many lives they currently have. You can do this by adding the following to the code: Printat (41,0); “You have “; lives; “ lives left.” Printat (0,0); “Welcome to Cosmic Adventure!”

The printat command will specify a location on the screen to display the text using x,y.

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STEP 3

Let’s add a way whereby the user is required to press a key to continue, this way you can leave instructions on the screen for an indefinite period: Printat (15,15); “Press the Spacebar to continue…” While inkey <> 32 cycle Repeat

This prints the message whilst waiting for the specific key to be pressed on the keyboard: the Spacebar.

STEP 4

Now we can start the ‘story’ part of the adventure:

Cls Print “You awake to find yourself in an airlock onboard a space station.” Input “There are two buttons in front of you: Green and Red. Which do you press?”, button$ If button$=”Red” then Let lives=lives-1 Print “You just opened the airlock into space. You are dead!” Print “You now have “;lives; “ lives left.”


STEP 5

Now add:

If lives=0 then goto 25 Print “Press the Spacebar to try again.” While inkey <> 32 cycle Repeat Goto 8 Else Print “The door to the interior of the space station opens, lucky for you.”

We can now continue the game from line 29, adding another press the Spacebar routine, followed by a clear screen ready for the next part of the adventure.

STEP 8

Print “Press the Spacebar to continue…” While inkey <> 32 cycle Repeat Cls

The Goto command goes to a line number and continues with the code. Here you can use it to start an end of game routine.

You can now Save the code, call it Adventure (or something), and Run it from the menu. Whilst it’s not the most elegant code you will ever see, it brings in many different elements and shows you what can be done with FUZE BASIC.

STEP 9

STEP 6

Let’s finish this routine off with:

Endif Endif Goto 29 Print “Sorry, you are dead. End of game. Press Spacebar to start again.” While inkey <> 32 cycle Repeat Goto 1

This closes the If statements, then goes to line 29 (if you pressed the Green button) to continue the game, skipping the end of game routine.

From line 25 we start the end of game routine as stated on line 15, goto 25. This only works if the variable lives equals 0; the player’s lives have run out. It prints a ‘sorry you are dead’ message and asks to press the Spacebar to start the game all over again from line 1, the goto 1 part.

STEP 7


Before you continue with the adventure, and map the fate of our reluctant space hero, we’re going to improve our code with some graphics. FUZE BASIC has some great graphical commands at its disposal, along with some other useful and interesting extras.

STEP 10


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Coding with FUZE BASIC Part 3 The last tutorial had you creating the foundations for a text-based adventure game. Whilst it works perfectly fine, it would be nice to include some graphics and maybe a few other elements to have it stand out from the usual BASIC programs. ADDING GRAPHICS

FUZE BASIC employs a variety of different commands to display graphics, either drawn on the screen or by displaying an image file.

STEP 1

You’re going to start by making the game full screen, then adding an appropriate image that sets the theme of the adventure. From line 2 press Enter, to create a new line 3, and type in the following: Fullscreen=1 Spriteindex=newsprite(1) Earth$=”planetEarth.png” Loadsprite (earth$, spriteindex, 0) Plotsprite (spriteindex, 200, 200, 0)

STEP 3

Now create a new line 13, by getting the cursor to the end of line 12 and pressing Enter. For the new line, type in:

Hidesprite (spriteindex)

This command will remove the image from the screen, allowing you to include a new image for the next step in the game.

You may need to source your own images for your game. In our example, we found an image of red and green buttons and copied to the /Desktop/fuze-basic/extras/images folder. Now we need to add it to our code from line 15:

STEP 4

STEP 2

The code from Step 1 will import and display an image of the Earth; the image itself is already available in the /Desktop/ fuze-basic/extras/images folder. It’s now classed as a sprite and can be manipulated through the various graphical commands of FUZE BASIC. Any unique images you want to include should be copied to this folder to add to your game.

buttons$=”buttons.png” loadsprite (buttons$, spriteindex, 0) plotsprite (spriteindex, 300, 400, 0)

Make sure the image is called before the Input command!

Continuing, we can use images of the interior of the ISS if the Green button is pressed. Download the image, put it in the images folder, name it ISS.png and call it from the code whilst hidesprite hides the previous image.

STEP 5

Hidesprite (spriteindex) U;date Print “The door to space station opens..” ISS$=”ISS.png” Loadsprite (ISS$, spriteindex, 0) Plotsprite (spriteindex, 200, 200, 0)

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By now your code is getting quite hefty. Don’t forget that with each new line you’re entering, the original Goto values will be different. It’s best to return to the code and update the lines where Goto is referenced.

STEP 6

STEP 7

Naturally you can continue with Cosmic Adventure yourself, adding choices, graphics and keeping tabs on the number of lives and whatever else you can think of. As we said, it’s not the most elegant code and it’s as far from a triple-A game as you can imagine; but at least it’s given you a head start with FUZE Basic.

STEP 8

Additionally we can add an image for the End of Game routine and insert the code from line 39:

Print “Sorry, you are dead.” Gameover$=”gameover.png” Loadsprite (gameover$, spriteindex, 0) Plotsprite (spriteindex, 200, 200, 0) While inkey <> 32 cycle Repeat Hidesprite (spriteindex) Goto 1 Here’s a recap of the images we’ve used for the graphics in our adventure game. The FUZE BASIC manual comes with countless more commands to make better use of the system, so read through it and expand on what you’ve learned here.

STEP 10

Once more, the code has now expanded and as such you need to ensure that any reference to another line is updated to reflect the new numbering; especially lines 24 and 38, which call either End of Game routine or continue the game if the Green Button has been pressed.

STEP 8



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Using a Breadboard A great way to learn circuits is to use a breadboard. You can use a breadboard with FUZE BASIC, or Scratch and Python, to control LEDs and other simple circuits. Here we’ll show you how a breadboard works. GPIO

The Raspberry Pi enables you to access electronic pins, known as GPIO (General Purpose Input and Output). These are used to interact with external electronics like LED lights and switches. To start with you’ll learn to build circuits using a tool known as a Breadboard.

STEP 1

The FUZE Workstation comes with a breadboard and some basic electronics components - you can follow along with this tutorial by getting a breadboard, 1 x blue and 1 x red breadboard wires, a 5mm LED, a 22Ohms 5% resistor, 9V battery, and a 9V snap battery clip. Your local electronics shop will help you out.

STEP 3

The red and blue lines are power rails: red is for positive and blue is for negative. The holes do not provide any power themselves; instead they just connect to each other. So if you plug an item into one hole, and another item into a connected hole (along the line), then the two are connected as if you’d physically joined the two things together.

STEP 2

Get out the breadboard, hold it up vertically and take a good look at it. You should see four vertical columns. The two pairs, on the left and right, both have a red and blue line running vertically alongside them. In the middle are vertical columns with letters and numbers. There are typically two main columns, lettered A-E and F-J.

STEP 4

The two columns of holes on the outside are connected all the way down the line from the top to the bottom. Take a 9V battery and attach a snap battery clip. Connect the positive wire (red) to the topmost red hole on the left, it will provide positive power to any wire or component connected in any red hole all the way down to the bottom. Add the blue (negative) wire to the topmost blue hole on the right.

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Using a Breadboard

The two columns on the inside of the breadboard work completely differently. They are not wired vertically, but horizontally along the row of each columns. So if you look at row 1, the holes marked A, B, C, D and E are connected; and the holes in rows F, G, H, I and J are connected. What do we mean by “connected”? Let’s do it physically first to find out.

STEP 5

Get the LED and look at it closely. Notice how one leg is longer than the other. That’s the positive wire; the shorter one is negative. Take a resistor and wrap one end of it around the shorter wire on the LED. Take the positive wire from the PP3 battery clip and touch the LED; touch the negative wire to the resistor and see the LED light up. We’ve numbered these 1, 2 and 3 so you can match them in the next steps.

STEP 6

RECREATING THIS IN A BREADBOARD

Wrapping wires and circuits around each other isn’t going to be much fun, especially when you’re trying to figure out how something works. That’s what a breadboard is for: the holes enable you to connect one item to another. Let’s now recreate this simple LED circuit on a breadboard. With the positive and negative cables from the battery connected to the top of the power rails, take a red connector and slot one end into a hole on the red line, and the other end into hole A1.

STEP 1

This is the part where most people mess up. Take the other leg of the LED and connect it to hole D2. This is the next row down. If you connected it to another hole on line 1, such as D1, it would be the equivalent of touching both LED legs together.

STEP 3

Now take your resistor and place it next to the LED leg in slot E2 (also on the second line). If you look at the photo from Step 6, this is the equivalent of 2 (the part where the LED and resistor are connected. Insert the other end of the resistor in a hole on the negative power rail and your LED will light up.

STEP 4

Now take the LED, find the long end, and slot this into hole B1. This is the equivalent of number 1 in our physical connection. The red cable is connected vertically along the powerline, and then to row 1 on the breadboard where it is connected horizontally to the LED on row 1.

STEP 2



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Using the FUZE IO Board So far our breadboard hasn’t been connected to the FUZE or Raspberry Pi in any way, but all that’s about to change. We’re now going to remove the battery and slot our breadboard into the FUZE. GPIO PINS

The Raspberry Pi’s GPIO pins act as a physical interface between the Raspberry Pi and electronic items. On the FUZE these are safely connected to the IO board, and can then be connected to your breadboard.

STEP 1

Remove the 9V battery and battery clip if it is still connected to the breadboard, and slide the breadboard into the top of the FUZE so the wires and LED are near the IO board. Let’s take a closer look at what the IO board has to offer.

STEP 3

The pins marked “GPIO” and numbered 1-7 are more interesting. These can be turned on or off from inside programs, or at the command line. When turned on they provide 3.3V, and when off they provide nothing. These On/Off switches can be used to activate and deactivate components you attach to the Raspberry Pi.

STEP 4

STEP 2

If you look closely at the IO board you’ll see a section of pins marked “RPI Header”. These match the pins that are on your Raspberry Pi. On the right side of the board are a number of output sockets. The PWM and supply sockets provide steady power (3.3V or 5.0V as marked).

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Start by connecting a blue cable to the pin marked GND in the Supply section on the top right of the FUZE IO board. Connect the other end to the leftmost hole in the blue rail, now running along the top of the breadboard. Connect a red cable to the socket marked 3.3V on the supply section in the bottom right of the IO board. Connect the other end of the cable to first hole in the red rail running along the bottom of the breadboard. The LED will come on.

Using the FUZE IO Board

This isn’t any different to what we had before, so let’s spice things up. Remove the red cable from the 3.3V IO socket and connect it to the socket marked 0 underneath GPIO. The LED will turn off. This is because this socket won’t provide any power until we tell it to.

STEP 5

STEP 6

Start FUZE BASIC and enter:

PinMode (0, 1) DigitalWrite (0, 1)

The LED turns on. The first part, PinMode, tells the Raspberry Pi that GPIO 0 is going to be used, and the 1 part says it will be output. The DigitalWrite command sets GPIO 0 on. Enter DigitalWrite (0, 0) to turn the LED off.

GETTING INPUT

We’re now really steaming along. Our Raspberry Pi-powered FUZE is turning on LED lights in the outside world. Next we need to look at input; how we can get information from our breadboard to our Raspberry Pi.

STEP 1

Remove the LED and resistor from the breadboard and remove the GPIO 0 and GND cables. Place the Push button switch in the same place as the LED (B1 and D2) and place the blue cable in the hole next to it (E2). Take a look at the photo if you need help placing the items in the right holes.

Press F2 to open the Program Editor. Enter the following program: PinMode (0, 0) Until DigitalRead(0) Cycle Repeat Print “Button Pushed” Press F3 to run the program.

Now take the blue cable in E2 and connect the other end to GPIO 0. Finally, connect the red cable from the first hole in the power rail to 3.3V. Our circuit is complete. Current will go from the 3.3V to the power rail, and from the power rail to our switch. The switch is connected to our blue cable, which connects to GPIO.

Here’s what happens. Power is flowing from the 3.3V socket to the switch where it stops. Meanwhile our program has set GPIO 0 to 0 (input mode) and a Cycle Repeat loop is waiting until input comes through on 0 (via DigitalRead). When we push the button a connection is made, power flows to GPIO 0 and it alerts the program. It then prints the message “Button Pushed”.

STEP 2


STEP 3

STEP 4


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Using a Robot Arm with FUZE BASIC As part of the educational kit, the FUZE Workstation can be purchased with an accompanying robot arm. This is a 149 piece kit-form robotic arm, that requires assembly and is powered by four D-type batteries. It’s connected to the RPi or FUZE via a USB cable and is also Windows compatible. I, ROBOT

We won’t go into the construction of the robot arm here, the instructions which come with the arm are easy to follow and it can be completed and ready for use within a couple of hours or so. Let’s look at how to get it working.

STEP 1

The robot arm is one of the first external hardware components that was released and fully compatible with the Raspberry Pi; as such, it’s an excellent project to get into, from the construction of the arm itself, to operating it via the FUZE Workstation.

STEP 3

To begin with, let’s look at a few commands to make the robot arm move. In Immediate Mode, in FUZE BASIC, enter:

ArmBody (1)

This starts the arm rotating clockwise (looking down on it).

STEP 4

Once the arm begins to rotate clockwise it will get to the limit of its range and start clicking. When it starts this quickly enter the command:

STEP 2

Start by plugging the robot arm into one of the spare USB ports on the back of the FUZE workstation. Ensure that the arm has its batteries correctly in place and that its power switch is On. Now open FUZE BASIC and remain in the Immediate Mode.

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ArmBody (0)

This will stop the arm from moving.

Using a Robot Arm with FUZE BASIC

STEP 5

Now enter: ArmBody (-1)

This will start moving the arm anti-clockwise. Again, when it starts to click enter the command: ArmBody (0)

To stop it from moving.

STEP 6

The other commands to make the arm move are:

ArmShoulder ArmElbow (x) – where x ArmWrist (x) – where x ArmGripper (x) – where ArmLight (x) – where x

(x) – where x can be 1, -1 or 0 can be 1, -1 or 0 can be 1, -1 or 0 x can be 1 -1, or 0 can be 1 or 0

STEP 8

Press F2, and type in the following:

PROC ResetArm PROC DisplayInstructions End DEF PROC ResetArm ArmBody (0) ArmShoulder (0) ArmElbow (0) ArmWrist (0) ArmGripper (0) ArmLight (0) ENDPROC DEF PROC DisplayInstructions CLS FONTSCALE (2,2) Ink = Red Print “I, Robot” Ink = White HVTAB (0,2)

This is the start of the program, resetting the arm and preparing the onscreen display.

Note: you can press the up arrow key to re-enter the previously typed commands, so you can quickly stop the arm’s movement when it reaches its limit.

STEP 9

Let’s create a program allowing you to move the arm around freely. There are some new commands here: PROC and DEF PROC, that enables BASIC to jump to a PROCedure, another part of the program, then back with ENDPROC. FONTSCALE determines the size of the on-screen print display and HVTAB is an X and Y coordinate system to print on-screen.

STEP 7

Now to expand the program to control the arm:

Print “Press:” Print Print “1 or 2 for Body Left & Right” Print “3 or 4 for Shoulder Up & Down” Print “5 or 6 for Elbow Up & Down” Print “7 or 8 for Wrist Up & Down” Print “9 or 0 for Gripper Open & Close” Print “Enter to turn the Light On or Off” Ink = Red Print “Spacebar to stop all movement and turn off the light.” ENDPROC

Now we need to process the user input. There’s a lot here but type the content as shown in the screenshot. Save the code and Run; you can now control the robot arm using the number keys 1 to 0, the Enter key for the light and Spacebar to reset everything.

STEP 10



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FUZE BASIC Examples – Part 1 FUZE BASIC has an impressive following of coding experts and enthusiasts who have selflessly provided their code for others to learn from and use. These stalwarts of FUZE BASIC have forged some amazingly detailed examples, which we’ll take a look at over the coming pages. CODE REPOSITORY

From fractal generators to encryption programs and animation, here are ten excellent examples of what others have done with a little patience and a lot of code.

EXAMPLE 1

James Cook’s Tree of Pythagoras is an impressive fractal, constructed from squares, that looks remarkably complex but takes up surprisingly little code. You can find it at www.fuze. co.uk/code-repository; just enter the code and Run it to be amazed.

EXAMPLE 3

This code will load any image and make it scroll across the screen from right to left. Put your image either in the /extras/images folder or simply in the same folder as the code itself. Save and Run and enjoy the image moving across the screen. See if you can modify it to full screen, or more.

EXAMPLE 4

In the Program Editor click the Load button and browse through the folder /fuze-basic/Demos until you find Shooter.fuze. With the program listing loaded, scroll down to line 247 and change the “player2.png” entry to “Player2.png” – adding a capital P. This is a basic side-scrolling shooter and you’ve just fixed an error in the code.

EXAMPLE 2

Simon Plouffe is a Mathematician who, back in the ‘70s, created some incredible cardiod images by dividing a circle into prime parts and drawing lines based on mathematical spaced points on the circumference. Anyway, enter this and be amazed:

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FUZE BASIC Examples – Part 1

EXAMPLE 5

gram that displays a rotating three dimensional box on the screen until you press the Escape key. It’s a fantastic learning resource and with a little time you can bend it to your will and use it in your own code.

EXAMPLE 6

Dogs in Space is a fun little game (found in /fuze-basic/ Demos) that features in-game music, sprite animation, collision detection, scoring and keyboard controls. Whilst it may not amuse you for too long, it’s benefit lies in the code examples that you can turn to your own future programs.

EXAMPLE 7

Click the Load button, and browse to /fuze-basic/Games. Open the file silv.fuze and have a look through the 784 lines of code before clicking the Run button. It’s quite complex but when you run it you can see why. Those of a certain age will no doubt recall spending a fortune on Space Invaders in the arcades!


EXAMPLE 8

FuzeFighter, also found in the Games folder, is another prime example of what can be done with FUZE BASIC. There’s in-game music, sound effects, animations, collision detection, scoring and a two-player element that can be worked into your own routines.

EXAMPLE 9

The Robot.fuze file, in the Games folder, is an extension to the previous tutorial’s robot movement BASIC program that you entered. However, this time there’s graphics and animations to help improve the process and make it a more flexible (excuse the pun) program

EXAMPLE 10

Finally, snake.fuze is a good example of a combination of programming elements. Graphics, scoring, collision detection and some interesting routines to help improve your overall program can be found within this code.


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FUZE BASIC Examples – Part 2 Continuing from the previous pages, here are ten more excellent examples of what can be done with FUZE BASIC. Take what you want from the code, alter it and insert it into your own routines to finetune your program. CODE STRIPPING

Many of the legendary programmers from the golden era of home computing stripped the code from snippets posted in the magazines of the time. They bent the code to their will and created something as close to magic as possible.

EXAMPLE 1

Amiga owners will have fond memories of their futuristic computer back in the late ‘80s and early ‘90s. The Amiga was a pretty impressive home computer, even by today’s standards and its iconic Bouncing Ball routine will forever be remembered by those who grew up with one. Load up aball.fuze from Demos and see what you can use.

EXAMPLE 2

Whilst an analogue clock on the screen, complete with second hand, may not sound too interesting, there’s a surprising amount of useful code within this particular routine. Clock.fuze is in the Demos folder and once loaded up you can strip all manner of handy code snippets from it.

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EXAMPLE 3

Scankeyboard.fuze is an extremely handy bit of code to load up. It’s a simple program that will display the key pressed on the keyboard, which is a great resource when it comes to creating keyboard interactions with the user and the program, such as a game. Just take the key codes you need and insert them in your own programs.

EXAMPLE 4

This code snippet will look for and detect any attached BBC micro:bit or Arduino compatible devices that you’ve attached to the FUZE IO or Raspberry Pi GPIO pins. It’s incredibly handy for helping you create the code behind your hardware project.

FUZE BASIC Examples – Part 2

EXAMPLE 5

This little snippet of code, although simple, will display some of the available font sizes of FUZE BASIC. The maximum size is 20, so alter as you wish:

EXAMPLE 8

If you want to incorporate mouse pointer and button use in your code, then this will certainly help you out. It’s a fairly simple bit of code but remarkably effective and it can easily be inserted into your own programs.

CLS FOR size = 1 TO 7 LOOP INK = RND(30) FONTSIZE( size ) PRINT “Hello” REPEAT END

EXAMPLE 6

If you’re working with a Raspberry Pi SenseHAT, then the following code will return the current value of the HAT’s accelerometer: CLS LOOP PRINT “Sense Accelerometer X=”; SENSEACCELX PRINT “Sense Accelerometer Y=”; SENSEACCELY PRINT “Sense Accelerometer Z=”; SENSEACCELZ REPEAT END

EXAMPLE 7

EXAMPLE 9

Including the use of a gamepad or joystick in your games or code is a great addition to also being able to redefine the keyboard. This code will detect and display the states of each of the axis and buttons.

And this code will return the value of the SenseHAT’s compass:

CLS LOOP PRINT “Sense Compass X=”; SENSECOMPASSX PRINT “Sense Compass Y=”; SENSECOMPASSY PRINT “Sense Compass Z=”; SENSECOMPASSZ REPEAT END


EXAMPLE 10

Finally, if you’re after something a little competitive with your family, then load up reaction.fuze from the Demos folder. When run, this code will test your reaction time by hitting the Spacebar when indicated. See how fast you can get it, and see if you can hack the code.


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Introducing Scratch Scratch is a powerful introduction to programming created by MIT (Massachusetts Institute of Technology). It’s an extremely high-level programming language designed to teach children the building blocks of programming. It’s highly visual with graphical characters known as sprites, backdrops and sound effects. These can be programmed in advanced or set to respond to user input. This makes it easy to create games and other visual projects.

Block Palette The commands are known as “blocks” and sit on the left in the Block Palette. The tabs at the top enable you to choose different categories such as Motion and Sensing.

Script Area Blocks are dragged from the Block Palette to the Script Area to form a script (or program). The blocks snap to each other to form a vertical column, which is much the same as command lines of computer code.

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Introducing Scratch

Toolbar Above the Stage sits a toolbar with some further options. To the left are Duplicate, Delete, Grow and Shrink. These commands are used to adjust the visual appearance of sprites on the Stage.

Stage Mode On the right of the Toolbar are three further buttons that can be used to adjust the Stage. They are Small Stage, Large Stage and Presentation Mode. The first two adjust the dynamic between the Script area and Stage, while Presentation Mode removes everything but the Stage.

Stage The Stage area displays the sprites being used in the project set against a backdrop. Typically the sprites displayed on the Stage respond according to the blocks in the script.

Sprite Info The Sprite Info area contains the name of the sprite, and its current x and y co-ordinates. Buttons to the left are used to lock the movement and rotation of the sprite.

Sprites The sprites displayed in the Sprites pane also appear on the Stage. These respond to the scripts. You can also click and drag sprites on the Stage to re-arrange them.

Sprites Pane Below the Stage is the Sprites pane. This displays the sprites being used in the project. Clicking a sprite in the Sprites pane changes the script in the Script Area. Each sprite has its own script.



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Getting Started with Scratch If you are completely new to programming then Scratch is the perfect place to start. With Scratch you can learn the building blocks of programming and important programming concepts in a highly visual interface. INSTALLING SCRATCH

Scratch is built into Raspbian with PIXEL and is installed by default, so you just start it up and you’re good to go. You may need to update it later on, to use electronic attachments like breadboards, but more on that later. For now follow the steps to get started.

STEP 1

Scratch runs from the PIXEL interface so enter startx if you’re in the command line. Now choose Menu > Programming > Scratch. The program opens in a new window, click the Maximise button on the right so you have plenty of space to view the window and all its contents.

STEP 2

You see the Scratch interface with a list of blue items in the Block Palette left, an empty Script Area and a stage. On the stage will be an orange cartoon cat, known as the Scratch Cat. This is the default sprite that comes with all new projects. You will also see smaller versions of the sprite above the Script Area and in the Sprites Panel.

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STEP 3

Let’s take a look at Scratch Cat. Use the mouse to click and drag him to position him on the Stage. Right-click Scratch Cat and choose Resize This Sprite. Click and drag the small resize icon that appears make Scratch Cat larger and smaller. Right-click the sprite again and choose Rotate This Sprite. Drag the rotate icon to spin Scratch Cat around.

STEP 4

Scratch Cat looks a little lonely on its white space, so let’s give it a background. Click the Stage icon in the Sprites Pane. The Script Area switches to Backgrounds displaying the background you have. Click Import, open the Indoors folder and choose a background. We choose spotlight-stage. Click OK.

Getting Started with Scratch

STEP 5

The background appears on the Stage and Scratch Cat looks a lot happier. Let’s create a script that moves him to the stage. Click Sprite1 in the Sprites Pane to select the cat and click the Scripts tab to return to the Script Area. Now click the blue Motion tab at the top of the Block Palette.

STEP 6

Drag the turn [15] degrees block (with an anti-clockwise symbol) from the Block Palette to the Script Area. Now drag the move [10] steps block and connect it to the bottom of the Turn 15 Degrees block (they will snap together). Change the 10 in move [10] steps to 100. Our program is now ready. Click the script (the two blocks) to see what it does. Scratch Cat will rotate and move towards the stage.

SAVING SCRATCH FILES Before you get stuck into programming with Scratch, take the time to learn how to save and open your files, and open other test programs. There are lots of Scratch programs available so it’s easy to learn alongside other users. Click File > Save As to save your project. Enter a name in the New Filename box; we called ours “Scratch_Cat_On_Stage”. As mentioned in the Unix tutorials, it’s important to avoid any special characters and spaces in your filenames, so use underscores “_” instead.

Lots of example Scratch files can be found on the MIT website at https://scratch.mit.edu/projects. The website features a version of Scratch designed to work in browsers too. You can download Scratch files from the Scratch website but many of them use the newer Flash 2.0 format (the files end in .sb2). These do not work in Scratch 1.4 on the Raspberry Pi.

You can also add a Project Author (your name) and some information in the About This Project box. You don’t have to add project information but it’s good form among programmers, especially when sharing files. Click OK. You’ll see a square flash across the screen but no other confirmation window.

Scratch 2.0 is unlikely to come to the Raspberry Pi soon. In the meantime, Scratch 1.4 files created by other Scratch users can be transferred to your Raspberry Pi using FTP (see “Setting up FTP”). Use File > Open in Scratch and select the file, then click OK, to load the program.

STEP 1

STEP 2


STEP 3

STEP 4


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Creating Scripts in Scratch The program that you need to create in Scratch is called a script (or possibly a bunch of scripts). In this tutorial we are going to take a look at how you construct your scripts to build up a program. VISUAL CODING

The scripts in Scratch are created by snapping together blocks. These blocks are similar to the code you find in more complex programming languages, such as Python, but much easier to understand.

STEP 1

Start a new Scratch project (choose File > New) and save it as Dancing_Cat. You’re going to put our cat and some other characters on a dance floor and get them to bust some moves. Click Stage, then Backgrounds and Import and choose party-room. Drag the Scratch Cat graphic around the Stage to find a good starting position.

STEP 2

Click on Sprite1 in the Sprites Panes and click the Scripts tab above the Scripts area. Make sure you can see the cat graphic and Sprite1 above your. Now click Control in the Blocks Pane and drag the when flag clicked block into the Scripts area. This block represents the start of our program and tells Scratch to run through the blocks below it, when you click the Green Flag icon above the Stage window.

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STEP 3

Click the Motion tab and drag the move [10] steps block and connect it beneath the when flag clicked block. A quick word about that [10]: when we write a number or word, inside those square brackets, that’s our way of saying you can choose a value. It’s known as a “variable” (because it varies). We’ll tell you what number or selection we’re using but you can use any you want. Play around.

STEP 4

It’s not much of a disco, so let’s add some sound. Click the sound tab and drag play drum [48] for [0.2] beats and connect it the to bottom of the stack of blocks. Click on the blocks and Scratch Cat will move and a sound will come from your monitor. If your monitor doesn’t have sound you may need to attach speakers to your Raspberry Pi.

Creating Scripts in Scratch

Dancing is a back and forth affair, so let’s get Scratch Cat moving back. Drag another move [10] steps block to the bottom of the stack. Now click the 10 and change it to -10 (minus 10). Entering minus figures moves the cat backwards. Drag another play drum block to the bottom of the script. Now click the [48] number to pick a different drum sound. We chose 35.

STEP 5

Scratch Cat only moves back and forth once, which isn’t much of a party. Click Control and drag the forever block to the Script Area. Carefully position it beneath the when [flag] clicked block but above the move [10] steps block. The script should nest within the two prongs of the forever block. Click the Green Flag icon to start the disco. Click the red Stop icon to end the program.

STEP 6

EDITING SCRIPTS

Nothing is set in stone and you can move your blocks in and out of scripts and even have several scripts, or parts of scripts, in the Script Area. Scratch is far more forgiving than other programming languages for experimentation. It’s pretty bad form to use the forever block (or a forever loop) in programming. Programs are supposed to run from start to finish. Even programs like Scratch have an end point when you quit the program. We want to replace the forever block with a repeat one. Click the forever block in your script and drag it down to separate it from the other blocks.

Now drag a repeat [10] block from the block list and connect it to the when [flag] clicked block in the Script Area. Now drag the top play drum block of the stack inside the repeat [10] block. If you drag the top block all the blocks underneath move with it, and the whole lot will be nested inside the repeat [10] stack.

Our move and play drum blocks are still nested within the forever block though and we want to keep them. Click the top-most move block and drag it out of the forever block. It’s now good to get rid of the forever block, so drag it to the left and back to the Blocks List to get rid of it.

You can position the stack anywhere on the Script Area and even keep the unused blocks around, although we think it’s good practice to keep only what you are using in the Script Area and remove any unused blocks. Click the Green Flag icon above the Stage Window to view Scratch Cat doing a short dance.

STEP 1

STEP 2


STEP 3

STEP 4


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Interaction in Scratch Our Scratch Cat is now dancing back and forth, but wouldn’t it be great if we could control him? In this tutorial we’re going to look at creating keyboard interactions in Scratch. Let’s get our disco cat really grooving. INTERACTIVE CONTROL

The only Control option you’ve looked at so far is the when [flag] clicked block, which starts the program. Once your program is running it does its thing, right up until it finishes. You’re going to use the other Control blocks to do something more interesting.

STEP 1

Open the Dancing_Cat program from previous tutorials. Select Sprite1 and click on Scripts so you can see the when [flag] clicked script. Now click Control in the Block Palette and drag the when [space] key pressed block to an empty part of the Script Area.

STEP 2

You can drag and rearrange the block scripts to any part of the Script Area. We like to have our when [flag] clicked script in the top left but it really doesn’t matter where they are. It’s also worth spotting that you now have more than one script for Sprite1. You can have multiple scripts for each sprite in your program.

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STEP 3

You’re going to make Scratch Cat jump up and down when you press the space bar. Click Motion and drag change y by [10] and clip it to the when [space] key pressed block. What’s with the “y”? This is what’s known as a “coordinate”.

STEP 4

The position of each sprite on the stage is shown using two variables, x and y. These are referred to as the “coordinates”. The x is the sprite’s horizontal position on the stage; while the y coordinate is the vertical position. Click and drag the sprite around the Stage and you’ll see the x and numbers change.

Interaction in Scratch

The centre of the Stage is x: 0 and y: 0. As you move the sprite up and to the right the numbers increase and as you move it left and down they decrease, going into negative numbers. So when you use the change y by [10] block it says, take the current value of y (the vertical position) and increase it by 10. That makes our cat jump up.

STEP 5

What goes up must come back down. So drag another change y by [10] block and attach it to the bottom of the when [space] key pressed script. Click the Green Flag and run the program. Now press the space bar and… oh no, nothing happens. You’ve just encountered our first “bug”.

STEP 6

FIXING YOUR SCRIPT

We know that there’s something wrong with our script and we want to see Scratch Cat jump when the space bar is pressed. So let’s quickly squash this bug and see it working. The problem is that computers are super fast and even highly visual programs like Scratch can move in the blink of an eye, and that’s what’s happening here. If you tap the space bar repeatedly while the program is running you’ll see Scratch Cat flickering as it jumps up and down.

Drag a wait [1] secs block from the Blocks Palette and insert it underneath the change [y] by 10 block. Now press the space bar on the keyboard to see Scratch cat jump up and then back down. Notice that you don’t need to press the Green Flag icon to run the program, the Green Flag starts our other script.

The challenge is that your motion controls move the cat instantly from one place to another, so fast that you can’t see. Sometimes this is fine, like the back and forth dance, but obviously you need to slow down the jump. Help is a hand. Click the Motion tab to view the Motion blocks.

We think Scratch Cat stays in the air a bit too long. We want a jump, not a levitation effect. Change the wait [1] secs variable to [0.25]. This is a quarter of a second and will give us a more fun hop. Press the Green Flag to start the script and tap the space bar whenever you want Scratch Cat to jump.

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Using Sprites in Scratch So far we’ve just got the one sprite in Scratch (the eponymous Scratch Cat). In this tutorial we’re going to add a second sprite, and see how to make the two sprites interact with each other. LOOK SPRITE

Sprites are 2D (flat) graphics drawn on top of a background. They are commonly used to display information in games such as health bars, scores or lives. Older games are composed entirely of sprites, just like our Scratch project.

STEP 1

You’re going to add another sprite to our project and a second character to the scene. One fun and quick way to do this is to click the Get surprise sprite icon at the top of the Sprites pane. This adds a random sprite to our scene.

STEP 2

Hmm… we have a bicycle, which isn’t really going to work. Right-click the sprite and select delete to remove it from the Stage. Click the new sprite icon to reveal a window with several selections. Open the Fantasy folder, choose robot3 and click OK.

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STEP 3

Notice that when you add the new sprite, all the blocks on the Script Area vanish. The scripts you built for Scratch Cat relate to that object, not to our new robot. Click on Sprite1 in the Sprites Pane to view the Scratch Cat scripts again. Then click Sprite2 to return to your robot.

STEP 4

Now that you have more than one sprite, it’s a good idea to rename them. Click the sprite2 text in the Sprite Info Pane above the Script Area and enter Robot. Now select Sprite1 and rename it ScratchCat. Notice the capitalisation and no spaces or uppercase letters. This is called CamelCase and you need to use it from now on for the names of all your sprites.

Using Sprites in Scratch

Select Robot and click Control. Drag a when [space] key pressed and change [space] to [right arrow]. Add a change x by [10] block beneath. Right-click the script and choose duplicate to create another. For the second script change the when [right arrow] key pressed to [left arrow] and change x by [10] to [-10].

STEP 5

Well it’s fairly obvious where this is going. Press the Green Flag icon and your ScratchCat object will start to dance (and still jumps with space), whilst your Robot object can be moved left and right using the arrow keys on your keyboard.

STEP 6

CHANGING COSTUMES

Your two objects Robot and Scratch Cat don’t have to look like a robot or cat. That’s just the name you’ve given to each sprite. The visual appearance is a costume and your objects can change their costume and look completely different. Select the Robot in the Sprite Pane and click the Costumes tab. The Scripts Area now displays the costumes being used by Robot, including his current look. Click Import and use the Import Costume window to choose a new style for your Robot. You’re going to go with monster1-a.

Click Import again and add a third costume, monster1-b. This is the same character in a different pose. You should get rid of the robot. Click the x icon next to the robot1 costume to delete it. Your object no longer acts like a Robot, so change Robot to Monster in the Sprite Info Pane. Now it’s the same object, with the arrow scripts and will move left and right.

Your object is still called Robot but now looks like a monster and the costume it’s wearing is called monster1-a. Notice above it is the robot1 costume. Your Robot can have more than one costume. Sprites can even swap costumes while the program is running. This can be used to create animation.

Let’s use costume changes to make him dance. Click Scripts and drag when flag clicked block to the Scripts Area. Attach a repeat [10] block and inside it place wait [1] secs. Change [1] to [0.5]. Click Looks and drag a next costume block into the repeat block. Click the Green Flag icon and watch the party.

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Sensing and Broadcast Learning how to make objects interact with each other is an important coding concept. In Scratch, you’ll learn how to make your sprites and scripts communicate with each other using the Sensing and Broadcast blocks. MORE INTERACTION

Earlier we looked at how you could interact with scripts using the keyboard to move the sprites but scripts and sprites can also interact with each other, sending messages and responding to events.

STEP 1

Scripts can broadcast messages to each other. These can be used to start other scripts or to respond to events. You’re going to get Your ScratchCat object to respond to the Monster and say “Watch Out!!!” if the two sprites touch. Select ScratchCat in the Sprites Pane so you can view its Script Area.

STEP 2

If is a big word in a computer program. Programs work around a few simple terms and “if this then do that” is one of them. On our stage, you want to say: “if Monster touches ScratchCat then ScratchCat says ‘Watch Out!!!’”. Click Control and drag an if block to the Script Area.

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STEP 3

The options for interaction between the sprites are found in the Sensing part of the Block Palette. The one you are looking for is touching, at the top. Notice that this is a different shape to ones you are used to. It is designed to fit in the slot next to our if block. Drag the touching block into the spare slot in the if block.

STEP 4

The touching block responds to the condition of our sprite; in this case if it’s touching another sprite. You need to tell it which one. Click the arrow in the touching block and choose Monster from the list. There are a couple of default options: mouse pointer and edge. These are handy if you’re making games.

Sensing and Broadcast

You’ve got your if, what you now need is a response. Click Looks and drag a say [Hello!] for 2 secs block and insert it inside the if block. Change [Hello!] to [Watch Out!!!]. Try to run the program. Nothing happens! That’s because your if script isn’t part of the when flag clicked script.

STEP 5

How do you get your if script to run alongside the other scripts? You could put the if block inside when flag clicked but then it would look big and ugly and do two different things. You could add a second when [flag] clicked block to the if block but it would only work if they were touching at the start. The answer is to use a broadcast block.

STEP 6

BROADCASTING

The broadcast block enables one script to interact with the others. It can be used to tell scripts to run and is ideal for bigger projects where each sprite does several things at once. Click the Control tab in the Block Palette and look for the when I receive block. Drag this and connect it to the top of the if block. You need to set the receiver, the message it gets from the other script. Click the arrow next to receive to reveal the Message name window.

Now you need to broadcast that init message from your when [flag] clicked script so it runs at the same time. Drag a broadcast block to the Script Area and insert between the when flag clicked block and the repeat [10] block. Now click the arrow in broadcast and choose init.

You can call the message anything you want but it should start with a lowercase letter and in this instance you are going to use the word “init”. This stands for “initialise” and getting the lingo right now will make your life much easier when you move to a more complex language. Click OK.

Your program is almost ready but your if script only works once: when the Green Flag icon is clicked. You’re going to place it inside a Forever block. This is okay though, because it’s not your main program and you are also going to add a stop all block to the end of your when flag clicked block. Click the Green Flag to see your program run.

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Creating and Using Variables Variables are another building block of computer programs, and Scratch makes them easy to understand. With variables you can store values, such as a high score, player health or the items in a game inventory. WHAT IS A VARIABLE?

Variables, sometimes called “vars” for short, can be many different things. The two most common types are words (called strings) such as a player’s name; or numbers (called integers) such as a score or health.

STEP 1

You’re going to leave the disco behind. Choose File > New (click Yes if you have a project that needs saving). You’ll start with a blank stage containing a single Scratch Cat sprite. Click Control and drag a when flag clicked block to the Script Area.

STEP 2

You’re going to create a simple game where Scratch Cat rolls two dice and wins if they’re both the same number. Click Variables. Unlike other sections there are no blocks here, instead you have to create the variables you need. You need two, one for each dice.

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STEP 3

Click Make a variable and enter dice1 into the ? window making sure that your variable starts with a lowercase letter. There are two options here, For all sprites and For this sprite only. For all sprites allows every sprite to use the dice and this is known as a global variable.

STEP 4

For this sprite only means that only this sprite can use the two dice variables, this is known as a local variable. This is useful if you want to create another character with their own set of dice and play against each other. You’re doing that in the next tutorial, so choose For this sprite only and click OK.

Creating and Using Variables

STEP 5

A whole bunch of blocks appears in the Block Palette. You can now use your dice1 variable. However, you want two dice, so click Make a variable again and this time enter dice2. Remember to choose For this sprite only and click OK.

STEP 6

Both the dice1 and dice2 variables are currently empty. They could be anything you wanted but you want them to be a random number between 1 and 6. Drag the set [dice1] to [0] block and click it underneath the when flag clicked block. Drag another set [dice1] to [0] block underneath and change the [dice1] setting to [dice2].

SMOOTH OPERATORS

Operators are used to change the values of variables. Some of these will be familiar, you’ve used the addition operator ‘+’ to add two numbers together. Programs can also check if numbers are equal, bigger or smaller than each other or even not equal. Click the Operator tab and drag a pick random 1 to 10 block and drop it into the [0] in set dice1 to [0]. Change the [10] to a [6] so it reads set dice1 to pick random [1] to [6]. When you click the Green Flag it will pick a number between 1 and 6 and store it in the dice1 variable. Add a pick random [1] to [10] block to dice 2 and also set it to [6].

The = operator checks if two things are the same but you need to tell it to check our variables. Click Variables and drag dice1 to the space on the left of the = block. Drag dice2 to the space on the right of the = block.

You need to check the two dice. Click the Control tab and drag the if else block to the script. This block is like the if block you used before but it says, “if this happens, do this; if not, do this instead”. Now click operators and look for the = block. Drag it into the space next to if.

Finally Click the Looks tab and drag say [Hello!] blocks into the if and else spaces. Change the say [Hello!] text in if to [I win!!!] and in else to [Oh no. I lose!]. Click the Green Flag to play the game.

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Getting to Know Python Python has become one of the most popular high-level programming languages in use since it’s release twenty-six years ago. It’s a more powerful language than that of Scratch and BASIC but not as capable as that of C++ etc. However, it’s still an impressive programming language to learn and we will help you get started. Python Shell Python’s IDLE (Integrated DeveLopment Environment) has a Shell. The Python Shell enables you to interact with your programs and it makes it a lot easier to figure out what’s going on.

Run Python in IDLE The program you write in the IDLE Editor is run inside the Python Shell. Choose run > Python Shell to run a program or press F5. You will be prompted to save your program when you run it.

IDLE Editor The Editor is used to create and edit Python programs. It’s a built-in text editor that enables you to open, save and edit Python documents.

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Getting to Know Python

Python Document Python files are saved using the .py extension. They can be run from inside the Python IDLE or from the command line.

Python Code The Python programming language is more complex than Scratch or BASIC but it is clean to read and relatively easy to learn. It’s the next best step from starter programming languages.

Command

Line

Python can be accessed from the terminal command line. Enter Python to enter the Python Interpreter. This looks similar to the Unix command line, although you enter Python code not Unix commands.

Run from Command Line Python programs can be executed from the command line by entering Python3 followed by the name of the program, such as: python3 main.py. The program runs within the Linux command line and the results are displayed in the Terminal window.

Script Creation Python programs can be used to create scripts that run from anywhere inside the terminal shell. These can be used to create functions that work just like the ones built into the system.



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Start Using Python There are two versions of Python available: 2.x and 3.x. The 2.x version is the more popular but older, whereas 3.x is newer but doesn’t have as much support (although that’s increasing daily). We’ll look at using the latest version within these tutorials. IDLE PYTHON

We’re using the Python 3 IDLE in these tutorials, IDLE stands for Integrated DeveLopment Environment, or Integrated Development and Learning Environment.

STEP 1

Let’s start by opening the Python 3 IDLE. Choose Menu > Programming > Python 3 (IDLE). As we mentioned, Python 3 is the latest standard and whilst some of the code arrangements are different to that of Python 2, it makes sense to be up to date with the language.

STEP 3

Just as with FUZE BASIC, and other programming languages, Python uses strings, user input, can call external commands, files and other programs; and utilises variables to store data. For example: x=10 and y=20, then print (x+y). The print command requires the brackets in Python 3 to output to the screen.

STEP 4

STEP 2

Python will launch into the Python 3.4.2 Shell; the version number is regularly updated so don’t worry if yours is a more recent version. In here you’re able to enter programming commands directly. For example, start with: print (“Hello everyone!”) and press Enter.

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Whilst the Python Shell is a good place to experiment in, it’s not where most Python programs are created. Choose File > New File to open the Python Editor, a text editor used to write Python code. Enter: x = “Hello “ y = “everyone!” print (x+y)

Press F5, click OK to save the code and name the file.

Start Using Python

STEP 5

displayed; in this case, the words Hello everyone! as defined by the X and Y variables. Within the Shell you’re able to enter: print (X) and see the current values of the variables, being able to interact with them directly.

STEP 6

From the Editor window choose File > Open and select the python_games folder. In here you can find some premade games to look at. For example, select the starpusher.py file which is a Sokoban clone. Press F5 in the Editor and it opens a new window executing the code you’ve just loaded.

COMMAND LINE PYTHON

Whilst you’ll be spending most of your time in the Python IDLE, it’s worth knowing that Python code can also be created and executed from within the Terminal. Python is integrated throughout Raspbian, and can interact with the system itself. Close the IDLE Shell and Editor and open up a Terminal window. Python 2 can be accessed with the command: python; however we are using Python 3 and that is accessed in the Terminal by entering: python3.

To return to the Linux command line from within Python, enter: exit (). Whilst at the Raspberry Pi command prompt, locate the file you created earlier when using the Editor; ours was called Hello.py. Enter: nano Hello.py and change the values of x and y to someone’s name. Press Ctrl+x, then y and press Enter to save and exit nano.

The command line will change to >>> indicating that it’s ready for Python code. As before, with the IDLE Shell, you can enter code such as: print (“Hello everyone!”) and variables such as: x=10, y=20 and print (x+y).

Now let’s run the newly edited Python script from the command line. Simply enter: python3 Hello.py into the prompt; the contents of the Python code will be executed and the results returned to the Terminal window.

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Working with Variables You may be a dab hand at variables now after working with Scratch and BASIC but Python does things a little differently. These differences can be a little confusing at first but you’ll soon come to appreciate Python’s way of doing things. VARIOUS VARIABLES

We’ll be working with the Python 3 IDLE Shell in this tutorial. If you haven’t already, close down the Terminal from the last tutorial, and open Menu > Programming > Python 3 (IDLE).

STEP 1

In BASIC you were required to use a dollar sign to denote a string, which is a variable made up of multiple characters, such as the name of a person. In Python this isn’t necessary; for example, in the Shell enter: name=”David Hayward” or use your own name, unless you’re also called David Hayward.

STEP 3

As you’ve seen previously, variables can be concatenated using the plus symbol between the variable names. In our example we can use: print (name + “: “ + title). The middle part between the quotations allows you to add a colon and a space, as variables are connected without spaces, so they are added manually.

STEP 4

STEP 2

You can check the type of variable in use by issuing the type () command, placing the name of the variable inside the brackets. In our example, this would be: type (name). Add a new string variable: title=”Descended from Vikings”.

You can also combine variables within another variable. For example, to combine both name and title variables into a new variable, use: character=name + “: “ + title Then output the content of the new variable as: print (character) Numbers are stored as different variables: age=44 Type (age)

These are integers, which means a whole number.

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Working with Variables

However, you can’t combine both strings and integer type variables in the same command as you would a set of similar variables. You need to either turn one into the other or vice versa. When you do try to combine both, you get an error message: print (name + age)

STEP 5

This presents a bit of a problem when you want to work with a number that’s been inputted by the user, as age + 10 won’t work due to being a string variable and an integer. Instead, you need to enter:

STEP 8

int(age) + 10

This will TypeCast the age string into an integer that can be worked with.

The use of TypeCasting is also important when dealing with floating point arithmetic: numbers that have a decimal point in them. For example, enter:

STEP 9

STEP 6

This is a process known as TypeCasting. The Python code is:

print (character + “ is “ + str(age) + “ years old.”) or you can use:

shirt=19.99

Now enter: type(shirt) and you can see that Python has allocated the number as a ‘float’, because the value contains a decimal point. in quotes as the commas treat each argument to print separately.

print (character, “is“, age, “years old.”)

Notice that in the last example, you don’t need the spaces between the words in quotes as the commas treat each argument to print separately.

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STEP 7

Yet another example of TypeCasting is when you ask for input from the user, such as a name. For example, enter: age= input (“How old are you? “) All data stored from the input command is stored as a string variable.


When combining integers and floats, Python usually converts the integer to a float but should the reverse ever be applied, it’s worth remembering that Python doesn’t return the exact value. When converting a float to an integer, Python will always round down to the nearest integer (truncating); in our case instead of 19.99 it becomes 19.


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Creating Functions in Python Now that you’ve mastered the use of variables and operators, the next step is to tackle functions. You’ve already used a few functions, such as the print command, but Python enables you to define your own function. FUNKY FUNCTIONS

A function is a command that you enter into Python that does something. It’s a little piece of self-contained code that takes data, works on it, and then returns the result.

STEP 1

It’s not just data that a function works on. Functions can do all manner of useful things in Python, such as sort data, change items from one format to another and check the length or type of items. Basically, a function is a short word that’s followed by brackets. For example, len(), list() or type().

STEP 2

A function takes data (usually a variable) works on it, depending on what the function is programmed to do, and returns the end value. The data being worked on goes inside the brackets, so if you wanted to know how many letters are in the word antidisestablishmentarianism, then you’d enter: len(“antidisestabli shmentarianism”) and the number 28 would return.

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STEP 3

You can pass variables through functions in much the same manner. Let’s assume you want the number of letters in a person’s surname, you could use the following code (enter the text editor for this example): name=input (“Enter your surname: “) count=len(name) print (“Your surname has“, count, “letters in it.”) Press F5 and save the code to execute it.

STEP 4

Python has tens of functions built into it, far too many to get into in the limited space available here. However, to view the list of built-in functions available to Python 3, navigate to www.docs.python. org/3/library/functions.html. These are the predefined functions but since users have created many more, they’re not the only ones available.

Creating Functions in Python

Additional functions can be added to Python through modules. Python has a vast range of modules available that can cover a range of programming duties. They add functions and can be imported as and when required. For example, to use advanced Mathematics functions enter:

To use a function from a module enter the name of the module followed by a full stop, then the name of the function. For instance, using the math module, since you’ve just imported it into Python, we can utilise the square root function. To do so, enter:

import math

As you can see, the code is presented as module.function(data).

STEP 5

Once entered, you gain access to all the Math module functions.

STEP 6

math.sqrt(16)

FORGING FUNCTIONS

There are many different functions you can import created by other Python programmers, and you’ll undoubtedly come across some excellent examples in the future. Howevr, you can also create your own with the def command. Choose File > New File to enter the editor. Let’s create a function called Hello, that greets a user. Enter: def Hello(): print (“Hello”) Hello() Press F5 to save and run the script. You can see Hello in the Shell, type in: Hello() and it returns the new function.

To modify it further, delete the Hello(“David”) line, the last line in the script and press Ctrl+S to save the new script. Close the Editor and create a new file (File > New File). Enter the following: from Hello import Hello Hello(“David”) Press F5 to save and execute the code.

Let’s now expand the function to accept a variable, the user’s name for example. Edit your script to read: def Hello(name): print (“Hello”, name) Hello(“David”) This will now accept the variable name; otherwise it will print Hello David. In the Shell, enter: name=(“Bob”), then: Hello(name). Your function can now pass variables through it.

What you’ve just done is import the Hello function from the saved Hello.py program, and then used it to say hello to David. This is how modules and functions work: you import the module then use the function. Try this one, and modify it for extra credit: def add(a, b): result = a + b return result

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Conditions and Loops We’ve already looked at conditions and loops in BASIC and Scratch, so let’s now take a look at the Python way of doing things. Conditions and loops are what make a program interesting, they can be simple or rather complex. TRUE CONDITIONS

Keeping conditions simple to begin with makes learning to program a more enjoyable experience. Start then by checking if something is TRUE, then doing something else if it isn’t.

STEP 1

Let’s create a new Python program that will ask the user to input a word, then check it to see if it’s a four-letter word or not. Start with File > New File and begin with the input variable: word=input(“Please enter a four-letter word: “)

STEP 3

Now use an if statement to check if the word_length variable is equal to four and print a friendly conformation if it applies to the rule: word=input(“Please enter a four-letter word: “) word_length=len(word) if word_length == 4: print (word, “is a four-letter word. Well done.”) The double equal sign (==) means check if something is equal to something else.

STEP 4

STEP 2

Now you can create a new variable, then use the len function and pass the word variable through it to get the total number of letters the user has just entered: word=input(“Please enter a four-letter word: “) word_length=len(word)

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The colon at the end of IF tells Python that if this statement is true do everything after the colon that’s indented. Next, move the cursor back to the beginning of the Editor: word=input(“Please enter a four-letter word: “) word_length=len(word) if word_length == 4: print (word, “is a four-letter word. Well done.”) else: print (word, “is not a four-letter word.”)

Conditions and Loops

Press F5 and save the code to execute it. Enter a four-letter word in the Shell to begin with; you should have the returned message that the word is four letters. Now press F5 again, and re-run the program but this time enter a five-letter word. The Shell will display that it’s not a four-letter word.

STEP 5

Now expand the code to include another condition. Eventually, it could become quite complex. We’ve added a condition for three-letter words: word=input(“Please enter a four-letter word: “) word_length=len(word) if word_length == 4: print (word, “is a four-letter word. Well done.”) elif word_length == 3: print (word, “is a three-letter word. Try again.”) else: print (word, “is not a four-letter word.”)

STEP 6

LOOPS

A loop looks quite similar to a condition but they are somewhat different in their operation. A loop will run through the same block of code a number of times, usually with the support of a condition. Let’s start with a simple While statement. Like IF, this will check to see if something is TRUE, then run the indented code: x = 1 while x < 10: print (x) x = x + 1

STEP 1

The difference between if and while is that when while gets to the end of the indented code, it goes back and checks the statement is still true. In our example x is less than 10. With each loop it prints the current value of x, then adds one to that value. When x does eventually equal 10 it will stop.

STEP 2


The For loop is another example. For is used to loop over a range of data, usually a list stored as variables inside square brackets. For example: words=[“Cat”, “Dog”, “Unicorn”] for word in words: print (word)

STEP 3

The For loop can also be used in the countdown example by using the range function: for x in range (1, 10): print (x) The x=x+1 part isn’t needed here because the range function creates a list between the first and last numbers used.

STEP 4


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Python Graphics Just like Scratch and BASIC, it’s possible to incorporate graphics in your Python programs. These can simply be used to indicate a button that interacts with electronics on the breadboard or they can be the content of your Python game. GOING GRAPHICAL

You can draw simple graphics, lines, squares and so on or you can use one of the many Python modules available, to bring out some spectacular effects.

STEP 1

One of the best modules to begin learning Python graphics is Turtle. The Turtle module is, as the name suggests, based on the turtle robots used in many schools that can be programmed to draw something on a large piece of paper on the floor. The Turtle module can be imported with: import turtle.

STEP 3

The command turtle.circle(50) is what draws the circle on the screen, with 50 being the size. You can play around with the sizes if you like, going up to 100, 150 and beyond; you can draw an arc by entering: turtle.circle(50, 180), so the size is 50 but you’re telling Python to only draw 180o of the circle.

STEP 2

Let’s begin by drawing a simple circle. Start a New File, then enter the following code: import turtle turtle.circle(50) turtle.getscreen()._root.mainloop() Pressing F5 saves the code and executes it as usual. You now have a new window open up and the ‘Turtle’ will draw a circle.

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STEP 4

The last part of the circle code tells Python to keep the window where the drawing is taking place to remain open, so the user can click to close it. Now, let’s make a square: import turtle print(“Drawing a square…”) for t in range(4): turtle.forward(100) turtle.left(90) turtle.getscreen()._root.mainloop() You can see that we’ve inserted a loop to draw the sides of the square.

Python Graphics

You can add a new line to the square code to add some colour: turtle.color(“Red”) You can even change the character to an actual turtle by entering: turtle.shape(“turtle”) We can also use the commands: turtle.begin_fill() and turtle. end_fill() to fill in the square with the chosen colours: in this case red outline, yellow fill.

STEP 5

You can see that the Turtle module can draw out some quite good shapes and become a little more complex as you begin to master the way it works. Enter this example: from turtle import * color(‘red’, ‘yellow’) begin_fill() while True: forward(200) left(170) if abs(pos()) < 1: break end_fill() done() It’s a different method but very effective.

Now let’s get the code by importing the Pygame module: import pygame pygame.init() img = pygame.image.load(“RPi.png”) white = (255, 255, 255) w = 900 h = 450 screen = pygame.display.set_mode((w, h)) screen.fill((white)) screen.fill((white)) screen.blit(img,(0,0)) pygame.display.flip() while True: for event in pygame.event.get(): if event.type == pygame.QUIT: pygame.quit()

STEP 8

STEP 6

Yet another way in which you can display graphics is by using the Pygame module. There are numerous ways in which Pygame can help you output graphics to the screen but for now let’s look at displaying a predefined image. Start by opening a browser and finding an image, then save it to the folder where you save your Python code.

STEP 7


In the previous step you imported Pygame, initiated the Pygame engine and asked it to import our saved Raspberry Pi logo image, saved as RPi.png. Next you defined the background colour of the window to display the image and the window size as per the actual image dimensions. Finally there’s a quick (and dirty) loop to close the window.

STEP 9

Press F5 to save and execute the code and your image will be displayed in a new window. Have a play around with the colours, sizes and so on and take time to look up the many functions within the Pygame module too.

STEP 10


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Raspberry Pi Projects

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Raspberry Pi Projects INDEX

Raspberry Pi Projects The Raspberry Pi has become famous not just for being an affordable, mini computer but also for the amazing projects that have been dreamt up by its ever increasing userbase. We’ve seen the Raspberry Pi taken into space onboard the International Space Station, used as a media server in the living room, to control robots and even used in conjunction with other Raspberry Pi’s to form an interconnected super computer. We look at some of the brilliant, challenging and fun projects that you can accomplish with your Raspberry Pi, as well as including some of the many robot kits available, that you can use to astound and amaze your friends and family.


148 Create a Music Streaming Box

160 Create a Supercomputer

150 Create a Media Server

162 Build a CamJam EduKit Robot

152 Build a Retro Games Console

164 Controlling Your Robot

154 Raspberry Pi Portable Games Console

166 Add Sensors to Your Robot

156 Set Up a Time-lapse Webcam

168 Turn an RC Toy into a Robot

158 Build a Web Server

170 Using GitHub


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Create a Music Streaming Box Use Pi MusicBox to turn your Raspberry Pi into a stand-alone streaming music player for services like Spotify, Google Music or SoundCloud. Attaching your Pi MusicBox to an old Hi-Fi gives it the very latest multimedia powers. PI MUSICBOX

You can turn your Raspberry Pi into a cracking music centre. Add the Pi MusicBox software and connect your Raspberry Pi to a set of speakers.

STEP 1

Download the Pi MusicBox software from www. woutervanwijk.nl/pimusicbox. The process for installing the Pi MusicBox image is the same as when installing Raspbian. Use dd bs=4m if=~/Downloads/musicbox0.6/ musicbox0.6.img of=/ dev/rdisk4 on a Mac or linux computer or win32DiskImage on a windows PC.

STEP 2

Once the image files are copied to the SD card, use the file manager to browse the MUSICBOX SD Card and open the config directory. Open the settings.ini file in a text editor. Scroll down to find wifi_network=”” and wifi_password=””. Enter your network and password details inside the quote marks. Save the file.

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STEP 3

Eject the SD Card from your computer and place it into the Raspberry Pi. Make sure you have the Wi-Fi dongle attached and insert the SD Card into your Raspberry Pi. You don’t need to attach the Raspberry Pi to a display, but you can use a display to check that it boots correctly the first time. Don’t power it up just yet.

STEP 4

We’re going to add some music files to a USB Thumb drive. Attach a thumb drive to your computer and ensure that it is formatted to the FAT-32 (use Disk Utility on a Mac and choose MS-DOS FAT as the Format option; right-click and choose Format on a Windows PC). Copy music files and folders to the thumb drive.

Create a Music Streaming Box

Eject the USB Thumb Drive from your computer and attach it to the Raspberry Pi. Now connect a 3.5mm mini jack cable to the audio out connection on your Raspberry Pi or you can attach headphones just to test it out.

STEP 5

Attach the other end to the input on your speaker or Hi-Fi. Finally add the power connection to your Raspberry Pi. If you have a display connection it will show the boot process and login. You don’t need a display though, you connect to Pi MusicBox from a web browser using http://musicbox.local.

STEP 6

SETTING UP PI MUSICBOX

Now that you have the hardware set up and the Pi MusicBox software installed it’s time to set it up to play your music. Pi MusicBox will play the music on your thumb drive, as well as from a wide range of services like Spotify and Google Play. Open a browser on your computer and enter http:// musicbox.local from your browser. You should see the MusicBox interface (as shown). Click Browse > Local Media > Tracks and pick a song. It will start playing through the headphones / speakers. Click Now Playing to view the controls for the track.

STEP 1

You can access the musicbox.local web service from a smartphone and manage your music. If you have an Apple device, you should turn AirPlay on. Choose Settings > Music and set AirPlay Streaming to On. You will now see MusicBox as an option in AirPlay in iTunes on your computer or in apps on your iOS devices.

You can also add music services such as Spotify or Google Play by entering your password. Click Settings and the Add (+) icon next to each service you want. Enter your user ID and Password. To set up Google Play you will also need a device ID of your Android phone, which you can get by dialling *#*#8255#*#*.

STEP 3

STEP 2


Other settings, such as YouTube, Last.fm and Soma Radio just need to be set to On to work. Click Update Settings to reboot your Raspberry Pi with the new services activated. Now use the Search field to look for any tracks, radio stations or artists that you want to hear. Select the tracks you want and play away.

STEP 4


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Create a Media Server With its tiny dimensions and HDMI connection, the Raspberry Pi is ideally suited to become a great media server. It’s amazingly easy to set up a Raspberry Pi to stream the latest movies and TV shows. Here’s how to get started. KODI CAN DO

The software used to turn your Raspberry Pi into a media centre is called Kodi, although some people call it XMBC (who develop the software). It’s opensource, so there are lots of customised versions available.

STEP 1

The easiest way to set up and use Kodi on your Raspberry Pi is to use NOOBS and install the LibreELEC option. You’ll need to connect your Raspberry Pi to the Internet so it can download additional files for the installation. Follow the NOOBs tutorial to install NOOBS but choose LibreELEC RPi2 and click Install.

STEP 2

When the Raspberry Pi starts up, you will see a Welcome screen. Ensure the Regional Settings are set to English (or choose your preferred language) and click Next. By default the device will be configured with OpenELEC as the hostname. You can change this if you want (we’ll leave it as is for now). Click Next.

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STEP 3

Your Raspberry Pi needs to be connected to the Internet to fulfil its potential as a media server. You can connect to the Internet using Ethernet, or by attaching a Wi-Fi dongle to the Raspberry Pi. It’s best to use Ethernet to set up the Raspberry Pi. Check that the network is available and the Raspberry Pi has an IP address. Click Next.

STEP 4

You can connect to OpenELEC using SSH. Click SSH under Configure Services. Samba should be highlighted by default. Ensure that both services are selected and click Next. Be sure to note the default user (root) and password (openelec). Click Next and Next again to start using the media centre.

Create a Media Server

Copy media files to a USB thumb drive and attach it to the Raspberry Pi. Click Videos > Files and the USB drive will appear. Select it to view the media files. You can also copy media files directly to the Raspberry Pi using SMB. Choose Go > Connect to Server on a Mac, or My Computer > Map Network Drive on a Windows PC.

STEP 5

Select the file and it will start playing. Press the space bar to pause the movie, and use the arrow keys to fast-forward or rewind. Press M, or move the mouse, to access on-screen controls. Here you can access subtitles, video and audio settings and other options. Press X to exit the movie and return to the main interface.

STEP 6

TAKING THINGS FURTHER

Now that your Raspberry Pi is set up as a media centre, you’ll want to hook it up to your TV and start watching the latest movies. Not so fast… a few more things will make it much easier to use. It’s not much fun controlling a media centre with a keyboard and mouse. Fortunately there is a much easier way to interact with Kodi, and that’s by using an app on your iPhone or Android phone. Point your web browser to kodi.tv/download/ and scroll down to Other Software to find links to the latest app for your device.

Tap Kodi (OpenELEC) in the list of devices to connect to your Raspberry Pi. You should see a list of Music, Movies, TV Shows, Pictures, Live TV and Now Playing. These can be used to find media stored on your Raspberry Pi. Tap Remote Control to directly control the media centre.

We’re going to use the iPhone remote, but the process is the same for each device. Make sure both your iPhone and Raspberry Pi are on the same network. Open the Kodi app and tap Add Host. Tap Find Kodi and it should automatically find the Raspberry Pi on your network (if not you’ll need to fill out the fields). Tap Save.

One last thing you should check out are Add-ons. These are used to expand the functionality of your Kodi media centre. Tap Videos > Add-ons > Get More > iPlayer and click Install. The BBC iPlayer app is quickly installed, and you can access it via Videos > Add-ons > iPlayer.

STEP 1

STEP 2


STEP 3

STEP 4


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Build a Retro Games Console The Raspberry Pi is way more powerful than computers of old, and that means it can emulate lots of old computers, games consoles and even arcade machines. This offers a whole world of nostalgia, and enables you to work with classic computers. GETTING RETRO

An emulator turns your modern Raspberry Pi into an older machine. It pretends (emulates) the classic computer or games machine. There are lots of emulators available, but the best one for Raspberry Pi is called RetroPie.

STEP 1

You’ll need to install RetroPie on an SD card. Download the latest version of RetroPie from blog.petrockblock.com. Now use SD Card Formatter (www.sdcard.org) to erase your SD card. It should be 4GB minimum, although we recommend 8GB if you want to use RetroPie to play games.

STEP 2

When the RetroPie image has downloaded, unzip it and copy the image to the SD card using sudo dd (on a Mac and linux machine) or win32 Disk Image (sourceforge.net/projects/ win32diskimager/) on a windows PC. Follow the guide for installing Raspbian (raspberrypi.org/downloads) if you need a reminder on how to use dd to copy image files.

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STEP 3

If your SD card is larger than 4GB you will need to expand the root file system in order to use the whole card. When RetroPie boots you will see a screen saying Welcome and No Gamepads Detected. Press F4 to exit to the command line. Now enter sudo raspiconfig to enter the Software Configuration Tool.

STEP 4

Choose Expand Filesystem and Ok when you see the Root partition has been resized window. Choose Finish and Yes at the Would you like to reboot now window. RetroPie reboots and returns you to the welcome screen. Hold down any key on your keyboard to set it up as the gamepad.

Build a Retro Games Console

The screen will switch to Configuring. Press the Up key on the keyboard to configure it as the up control. Now press Down, Left and Right. You can pick any keys you want for A, B, Start and Select (we like Z, X G and H). Finally set Page Up, Page Down and press Z (or the key you choose) for OK.

STEP 5

Now you’ll be presented with a horizontal menu of computers to choose from. Use the left and right keys you chose to pick a computer system. More computer systems and games consoles will appear as you add ROMS to the SD card. ROMs are small files that represent the tapes, floppy disks or cartridges that are used to contain programs (such as games).

STEP 6

ADDING ROMS

You can add ROMs to RetroPie using an FTP program such as Filezilla (filezilla-project.org). See page 50 for more information on setting up FTP and transferring files from your computer to a Raspberry Pi. You can download ROMs (video game files) from the Internet and to your RetroPie installation. Here they will be available for you to use. It is illegal to download ROMs protected by copyright. However, some ROM files have been made available for free, non-commercial use. Take a look at http://mamedev.org/roms/ to find files that you can access.

When RetroPie restarts you’ll see Mame appear as a new option in the main window. Press the key mapped to the A button (we mapped ours to the Z key). You will see the ROM added in the previous step in a list. Press the A button again to launch the ROM and start playing the game.

Open Filezilla and use the Site Manager (File > Site Manager) to connect to your Raspberry Pi. If you need to find the IP address of your Pi press F4 to exit from RetroPie and enter ifconfig. In the Remote Site section open RetroPie > ROMs > Mame. Copy the zip file from mamedev.org in your Downloads folder to the Mame folder.

You can now play the ROM game using the keys you mapped out earlier. The game is identical to the one that appeared on classic arcade machines (it is exactly the same code). As you add more ROMs from different computers and consoles they will start to appear in the RetroPie interface.

STEP 1

STEP 2


STEP 3

STEP 4


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Raspberry Pi Portable Games Console The Raspberry Pi makes a great retro games console and there are plenty of options out there. We love PiJuice’s Portable Games Console as it combines an analogue joystick with a 2.2-inch TFT screen. PORTABLE POWER

The Portable Games console uses a PiJuice (pi-supply.com), and a portable power pack for the Raspberry Pi with intelligent power functionality. This makes it possible for you to create projects that operate out in the world, such as our Portable Games Console.

STEP 1

First you’ll need to get all the parts. Along with the PiJuice and Adafruit 2.2-in TFT screen, you’ll need an Arduino Pro Mini, Analgue Joystick, 4 tactile switches and jumper leads. A complete list of materials can be found at: instructables.com/id/Raspberry-Pi-PortableGames-Console.

STEP 3

Right-angle headers are soldered onto the Arduino on the following pins: • Pin A0 - for input from joystick in x direction. • Pin A1 - for input from joystick in y direction. • Pins 2,3,4 and 5 for output of a digital state to the Raspberry Pi GPIO (up, down, left and right). • VCC and GRD for powering the Arduino. • VCC and GRD for powering the joystick.

STEP 4

Next, wires are soldered to the TFT screen: • A red wire with female end (~7cm) to 5V pin on TFT screen to power the Arduino. • A Black wire with female end (~7cm) to GRD on TFT screen. This is the pad marked with WP located on the underside of the screen.

STEP 2

The Portable Games console uses Adafruit Cupcade (designed for Adafruit’s Raspberry Pi Micro Arcade Cabinet). You can pick up a copy of the image file from learn. adafruit.com/cupcaderaspberry-pi-micro-miniarcade-game-cabinet/ hardware-setup. It’s a good idea to set up the Raspberry Pi as normal with the Cupcade installation and check that it works.

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Raspberry Pi Portable Games Console

The joystick output is two analog signals for x position and y position ranging from 0 to 5V. The Arduino is used as an analogue to digital converter (because the Raspberry Pi lacks analogue pins). Connect the Arduino to a Mac, PC or Linux computer using a USB to TTL adapter and install the Arduino software from arduino.cc/en/ main/software.

STEP 5

Download the PiJuice Portable Games Console software from github.com/pijuice/Games-Console. Make sure the Arduino is selected under Tools > Board and upload the software for the analogue to digital conversion.

STEP 6

ASSEMBLING THE CONSOLE

Now that you have all the parts and software ready, it’s time to start putting together the Portable Games Console. You’ll be playing arcade games on the move before you know it. Solder wire connectors to each tactile switch. Connect one side of each pin to a GPIO input. The other sides are made into a 4-1 junction and wired to the ground of the screen. To connect the other sides of each switch to the GPIO, right angle headers are soldered onto the GPIO breakout on the TFT screen.

STEP 1

First, two right angle pins onto pins 17 and 27, these will be the Insert Coin and Start buttons. Then a row of headers is soldered into pins 5, 6, 12, 13, 16, 19, 20 and 21 (four action buttons and four direction buttons).

STEP 2


STEP 3 • • • • • • • •

Use jumper leads to connect everything up:

VCC Arduino - VC Joystick GND Arduino - GND Joystick A0 Arduino - Joystick X A1 Arduino - Joystick Y 2 Arduino - GPIO 12 RPi 3 Arduino - GPIO 13 RPi 4 Arduino - GPIO 20 RPi 5 Arduino - GPIO 21 RPi

• VCC Arduino - 5V RPi • GND Arduino - GND RPi • Button 1 - GND RPi and GPIO 5 RPi • Button 2 - GND RPi and GPIO 6 RPi • Button 3 - GND RPi and GPIO 17 RPi • Button 4 - GND RPi and GPIO 27 RPi

Install Retrogame written by Adafruit to use the GPIO controls (github.com/adafruit/Adafruit-Retrogame). Check that everything is working correctly using a video game ROM. Once you’ve got the portable games console up and running you can start gaming. See Instructables (instructables.com/id/Raspberry-Pi-Portable-Games-Console/) for more help.

STEP 4


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Set Up a Time-lapse Webcam Connecting a webcam to your Raspberry Pi is a great first project. The hardware (a USB webcam) is easy to source, and you may have one already. It’s also pretty easy to set up and download the software. FILE RECORDING

We’re going to connect the webcam to the Raspberry Pi, and use a package called fswebcam to snap images as jpegs. We’ll then create a script that snaps photos on a regular basis and saves them into a folder.

STEP 1

First connect the webcam to a spare USB port on your Raspberry Pi. If you are using a Raspberry Pi Model A with no spare ports, you’ll need a USB hub. The quality of your images will vary depending on your webcam, and typically you’ll get higher quality photos using the Raspberry Pi Camera Module.

STEP 2

You need the fswebcam package to capture images. Enter sudo apt-get install fswebcam in the command line (if you are in LXDE, open terminal and enter the command). You’ll need to enter your admin password. You can learn more about fswebcam on the Firestorm website (http://www.firestorm.cx/fswebcam/).

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STEP 3

You can take an image by entering fswebcam followed by the filename you want the image saved as. Enter fswebcam image.jpg to take a photo from your webcam and save it in the home directory. You won’t be able to view this image if you are working in the command line, so enter startx to switch to the desktop.

STEP 4

Open a terminal window and enter ls to view the files in your home directory. You should see image.jpg (highlighted in pink). When using terminal from inside the desktop, you can open files from the command line using xdg-open. Enter xdg-open image.jpg to view the captured image using Image Viewer.

Set Up a Time-lapse Webcam

STEP 5

If you find images coming out blank or distorted, you need to set a slight delay to the webcam. Use the -S option to skip a couple of frames before snapping. Enter fswebcam -S 2 image. jpg to skip a couple of frames, then grab the shot.

STEP 6

You should also use the -r option to adjust resolution, and remove the time and date banner using --no-banner. Enter fswebcam -r 1024x768 --no-banner -S 2 image2.jpg to take a shot at a set resolution, with no banner and a slight delay. Now enter xdg-open image2.jpg to view it in Image Viewer.

TIME-LAPSE WEBCAM

Now that you’ve got a webcam program running on your Raspberry Pi, you can script it to run every minute, or every hour. With this script and a webcam you can turn a Raspberry Pi into a time-lapse camera. We need a directory to store the images and a script to capture them. Enter mkdir webcam to make the directory and nano webcam.sh to create the file. Now enter the following code: #!/bin/bash DATE=$(date +”%y-%m-%d_%H_%M”) fswebcam -r 640x480 --no-banner -S 2 /home/pi/webcam/$DATE.jpg Press Control+X to exit (enter Y to save the file).

STEP 1

We have an executable file. Enter ./webcam.sh to run the script (the ./ specifies the current directory) and ls webcam to check the directory for a saved file. Now we need to run this script once a minute. For that we need to edit a special file known as crontab. Enter crontab –e to view this file.

STEP 3

STEP 4 Our script saves images with the time and date in the webcam folder. The #!/bin/bash is known as a shebang and tells the shell to interpret it. The DATE= creates a variable set to the current time and date, which is used when saving the file. You need to make webcam.sh executable though so it can run; enter chmod 755 webcam.sh.

STEP 2


The crontab file opens in nano. Scroll down to the end and enter:

“* * * * * /home/pi/webcam.sh 2>&1”.

Press Control+X to exit and save the file. It will say installing new crongtab. The webcam now takes a snap every minute and places it in the webcam directory. You can find more information about crontab at www.adminschoice.com/ crontab-quick-reference.


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Build a Web Server Turn your Raspberry Pi into an Apache web server and serve up websites. Use it on your own network to build test websites, or get a static IP address to deliver your website to the Internet, directly from your Raspberry Pi. APACHE

Apache is an incredibly popular web application that runs more than half the servers on earth. Most websites you visit are delivered to you using Apache and it’s free to install and very easy to set up.

STEP 1

Open a terminal window, click LXTerminal in the Launch Bar, and enter sudo apt-get update. This will ensure that apt-get is using the latest versions of all its software. While it’s not vital to do this, it’s a good habit to get into from now on before installing any new software.

STEP 2

Now lets install Apache. Enter sudo apt-get install apache2 apache2-doc apache2-utils. You will be asked if you want to continue; enter y and press return. This installs the latest version of Apache 2, the Apache 2 documentation and a selection of utilities that will be handy as you work on your server.

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STEP 3

Apache will now be running from your Raspberry Pi and you can test it by connecting from another computer. First you need your Raspberry Pi’s IP address: enter ifconfig to get it. Now enter that IP number into a browser on your network and you should see: It works! This is the default web page for this server. The web server software is running but no content has been added, yet.

STEP 4

Before heading any further we’re going to add some additional functions to our server. PHP is a popular scripting language used to power many advanced websites; enter sudo apt-get install libapache2-mod-php5 php5 php-pear php5-xcache. Enter y and press return to install it.

Build a Web Server

We’re also going to install MySQL server. This is a popular open source database that’s used in by many online websites. Enter sudo apt-get install php5-mysql to get the PHP extension for MySQL and follow this up with: sudo apt-get install mysql-server mysql-client.

STEP 5

You’ll be asked to enter a password for the MySQL root user. Enter a password and press return. You’ll be asked to re-enter the same password again. When that is finished restart the Raspberry Pi using sudo shutdown -r now. When your Raspberry Pi restarts you’ll be ready to begin hosting your website.

STEP 6

CREATING YOUR WEBSITE

Now that you have Apache set up on your Raspberry Pi, it’s time to make something of it. Adjust the HTML and CSS files to build a basic website or use PHP to script a website. The It Works! web page is an indext.html file located on the file system. You can find it in /var/www/. Enter ls -l /var/www/ to see the index file. Notice that its owner is root not pi. Unlike most documents you work on, this one lives outside your home directory. Enter cat /var/www/index.html to view the contents of the file.

STEP 1

You’ll need to use sudo to edit the file. Enter sudo nano / var/www/index.html to view its contents. If you know HTML you can change the contents of this web page to whatever you want. Any edits you make can be checked by entering the IP address of your Raspberry Pi into a web server.

STEP 2


Alternatively you can open the Epiphany Web Browser inside the desktop and enter http://localhost. This will display the contents of the index.html file inside your web browser. You can create something more dynamic using PHP. Enter sudo rm /var/ww/ index.html to delete the index file and nano /var/www/index.php to create a PHP file in its place.

STEP 3

STEP 4

Enter this code into the website:

The date and time


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Create a Supercomputer String six Raspberry Pi computers together and build a supercomputer and experiment with Big Data. Cluster computing can teach you a lot about how modern computers work together to achieve great results. BUILDING A CASE

What’s better than a Raspberry Pi? Six Raspberry Pis all strung together to create a supercomputer known as a “bramble”; that’s what. Sung-Taek Kim, a software engineer from Korea has created the Pi Spark project (pocketcluster.wordpress.com).

STEP 1

With a bit of networking skill and the right project you can string multiple Raspberry Pis together. You’ll need six Raspberry Pi 2 models and a lot of wires and cables. This is housed in a unit made from four boards. Get the Schematics from github.com/stkim1/ pocketcluster/.

STEP 2

Used the schematics to get the boards cut. You can use a variety of materials, but the most popular way is to use a laser cutter with acrylic. If you don’t have your own cutter, then find a cutter near you (or use service like razorlab.co.uk).

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STEP 3

You’ll need a Photive 6-ports 50 watt USB charger; six 30 cm Cat6 Ethernet cables and six 30 cm 90 degree right-angled Micro USB to USB cables. Be sure to get right-angled USB to USB cables, as shown in the photo, or they won’t fit in the case.

STEP 4

You need a lot of screws and nuts for this project:

1) 2 x M3 Hex Nuts. 5) 24 x M2.5 5mm Screws. 2) 22 x M3 25mm Pillar Screws. 6) 24 x M2.5 Hex Nuts 3) 4 x M3 Whirled Hex Nuts. 7) 24 x M2.5 5mm Pillar Screws. 4) 6 x M3 4mm Screws.

Create a Supercomputer

The network router is an optional extra. You can connect the Raspberry Pi to an existing network but if you’re looking to create a truly independent setup then you can give it your own network switch. Be sure to choose something skinny like this D-Link 8-Port Gigabit Desktop Switch.

STEP 5

Once you have all the acrylic boards and screws you’re ready to start building the case. Start by putting the M2.5 5mm pillar screws on the boards and use M2.5 Hex nuts to tighten them up. Do this for all six sets as they will hold your Raspberry Pi boards in place.

STEP 6

BUILDING THE COMPUTER

Now that you have assembled the basics for your Raspberry Pi supercomputer, it’s time to start putting them all together. When you start the assembly process, the Pi Spark starts to look like the monster computer it’ll become. Use M2.5 screws to attach the Raspberry Pi to one of the acrylic boards. Make sure it is aligned the same way around as you see in the picture with the Ethernet socket flush against the side. Be sure to check that the Raspberry Pi is firmly attached to the board.

STEP 1

Apply two pieces of double-sided tape to the USB charger supporter – this is the small strip of plastic from the schematics. Place it in the middle of the piece called board-middle-end as shown in the picture. This strengthens the board so it can support the charger.

STEP 3

Now stack up each Raspberry Pi using the pillar screws. Notice how the devices are stacked, with the ones on the right positioned upside down. For more information on assembling the case look at pocketcluster.wordpress.com/2015/08/16/free-schematic-raspberry-pi-2-clusterassembly-tutorial.

STEP 4

Half of the boards are flipped to the other side of the acrylic board (check the schematics). This ensures that the Raspberry Pi power sockets are located near the power supply. The big round holes beneath each Raspberry Pi are for ventilation.

STEP 2



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Build a CamJam EduKit Robot The CamJam EduKit 3 is a fantastic robot kit that enables you to build a fully functioning robot with ultrasonic and line following sensors for just £17 / €19. All you need is a chassis and we’ll show you how to turn an old tin box into an amazing robot. CAMJAM

The Cambridge Raspberry Jam (camjam.me) teaches children of all ages how to build electronics projects and the kits are sold to everyone via the Pi Hut. The CamJam EduKit #3 has everything you need to build a robot (thepihut.com/collections/camjam-edukit).

STEP 1

The CamJam EduKit 3 includes wheels, motors, a battery box, an EduKit Controller Board and two sensors. You also get a breadboard, wires and resistors to bring it all together, along with some double-sided tape. We suggest you get a USB battery charger, the type used to recharge phones, and a Wi-Fi dongle.

STEP 2

You’ll need a chassis for your robot. We’re using a tin box (the type you often get to keep knick-knacks in). You can use any flat surface as a chassis, so long as you can mount the wheels but using a container makes it easier to hold all the bits inside. You could also use a plastic Tupperware box or even the box that the kit comes in.

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STEP 3

Flip the box upside down and make a hole in it in the middle, at one end. We’re using a metal drill to drill a hole through the tin box but if your box is made from plastic or card you could cut a hole using scissors. It doesn’t need to be large, just big enough to fit the wires from the servo motors.

STEP 4

Attach the two plastic wheels to the yellow servo motors making sure they’re on opposite sides. Now fix the servos to the underside of the box, making sure they’re near the hole you created. You can use the double-sided tape to mount the wheels but it’s a good idea to use Blu-Tack first to make sure the design works.

Build a CamJam EduKit Robot

Place four AA batteries inside the battery box and make sure it is set to Off. Use a small screwdriver to loosen the two central screws in the EduKit Controller Board. Place the black wire from the battery box in the GND and the red wire in VIN (Voltage). Take a look at Worksheet 1 (camjam.me/?page_id=1035#worksheets) for more info.

STEP 5

Place the robot front away from you and attach the red and black wires from the right wheel to the block marked Motor A – it doesn’t matter which way around. Take the wires from the left wheel and attach them to Motor B with the wires the opposite way around from Motor A (see picture).

STEP 6

SETTING UP THE RASPBERRY PI

The Raspberry Pi will need to operate on the move, so it needs power and a wireless network connection. You’ll also want to access it remotely, so you’ll want to set up VNC. Let’s build the brains. Install a fresh build a Raspbian Jessie on an SD Card. Use sudo apt-get update and sudo apt-get upgrade to get the latest builds for all your software. Now use sudo apt-get install tightvncserver to install VNC software. Enter sudo nano .bashrc and add vncserver to the end of your bash file so it starts at boot time.

Charge up a portable USB charger, the type normally use for mobile phones and make sure it’s got plenty of juice. Shut down your Raspberry Pi and plug in the portable charger and make sure it can boot and run your Raspberry Pi.

Connect a Wi-Fi dongle to your Raspberry Pi and click on the Wi-Fi icon in the top right of the Xcfc desktop interface; enter startx if you’re not in the desktop environment. Choose your network and enter the Wi-Fi password. Open the terminal and enter ifconfig: Make a note of your network address.

Check that the VNC connection is working from another computer. On a Mac press Control-K and enter the vnc://192.168.0.[x]:5901 (with x the number from ifconfig in Step 2). Click Connect and you should see the Xfce desktop. Your Raspberry Pi is now ready to work remotely inside the robot.

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Controlling Your Robot With all the motor parts in place, it’s now time to hook everything up and start testing out your robot. Once the motor control unit is attached to the Raspberry Pi and it is all powered up, you’re ready to start testing its movement in code. READY TO ROLL

Our robot still has a way to go to be complete but with the servos and wheels attached to the motor control unit and the power in place, it’s ready to start rolling around.

STEP 1

You should have all six wires attached to the EduKit Controller Board unit. Double check that the black wire from the battery is going to GND and the red wire to VIN and that the black and red wires to Motor A and Motor B are the mirror opposite way around (as shown in this photo). Gently push the motor control unit into the GPIO pins on the left side.

STEP 2

Now it’s time to power up your robot and see if it moves. Attach the battery pack to the Raspberry Pi and switch on the battery box. Give the Raspberry Pi 30 seconds to go through the boot process and connect to it from a computer using VNC and make sure it is responding.

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STEP 3

Open the CamJam website (camjam.me/?page_ id=1035#worksheets) and download Worksheet 2 - Running the motors. Open a text editor on your computer and type out the code for the 2-motors.py program. You can cut and paste it to your text editor but we think it makes more sense to type it line by line so you understand what it’s doing.

STEP 4

Open a FTP program such as FileZilla and choose File > Site Manager. Enter the IP address in the Host field, “pi” in the User field and your password (“raspberry” by default). Right-click on pi under Remote Site and choose Create Directory, name it “EduKitRobotics”. Now transfer the 2-motors.py file to the EduKit directory on your robot.

Controlling Your Robot

Open the VNC program and connect to your Raspberry Pi. You should see the Xfce desktop even if you set up the robot to book into the command line. Enter cd EduKitRobotics. Make sure your robot is on the floor and has about a meter of space in front of it. Now enter python3 2-motors.py and press Return.

STEP 5

STEP 6

All being well your robot should move forwards. If it moves backwards you need to swap the position of the red and black wires on both Motor A and Motor B. If it fails to move then check the wires to the motor control unit, check that everything is switched on and try replacing the batteries (you need good quality batteries with enough power to move the servos).

DRIVING CODE

Now that our robot is up and moving, it’s time to give it better control functionality. This code enables you to move the robot forward, backwards and rotate left and right. It also makes it easy to give the robot multiple directions in order. Head back to the CamJam website (camjam.me/?page_ id=1035#worksheets) and download Worksheet 3 - Driving and Turning. Type in the first block of code and save it as 3-driving.py in the EduKitRobotics folder. Make sure you enter the code from the section Moving the Robot at the end of your main block of code.

Take a good look at the Python code to see how it creates function definitions for Forwards(), Backwards() and StopMotors(). These definitions enable you to move the robot using functions, rather than typing out the code each time. Now add the Left() and Right() functions from the worksheet to the code.

The worksheet advises using nano to create code directly on your Raspberry Pi robot but we think it makes more sense to type it out on your computer and transfer it using FTP. Use VNC to connect to your Raspberry Pi and run the program using python3 3-driving.py. The robot should move forwards then backwards.

Add the movement instructions to the very end of the code and save the 3-driving.py program to your EduKitRobotics folder (using FTP to transfer it). Use VNC to run python3 3-driving.py on the Raspberry Pi. The robot should move forwards, rotate left, move forwards again, rotate right, move backwards and then stop.

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Add Sensors to Your Robot Now that our robot is built and moving around, it’s time to give it a brain. The two sensors can be used by the robot to react to its surroundings; either following a line or avoiding obstacles. ULTRASONIC AND LINE SENSING

Our robot has two sensors, an Ultrasonic and a Line Detector. The Ultrasonic is the one that looks like eyes and fits into the breadboard. The Line Detector has a small blue camera on one side and fits underneath the robot.

STEP 1

Open the CamJam website (camjam.me/?page_ id=1035#worksheets) and download Worksheet 4 and Worksheet 5. Worksheet 4 is just for the Line Detector, while worksheet 5 is for both sensors. Make sure you take a good look at the Building the Circuit diagram in Worksheet 5 and keep it with you during this tutorial.

STEP 3

Use a regular male-male jumper cable and place it next to the jumper in the breadboard (in the same column, fifth row). Connect the other end to the GND of the EduKit Controller Board. Now take another female-male jumper wire and connect it from the VCC pin on the Line Detector to the 3V3 (3.3 volts) pin on the EduKit Controller Board.

STEP 2

Make sure that the robot isn’t currently powered. If it is use VNC and shutdown the Raspberry Pi and disconnect the power to the Raspberry Pi. Locate one of the female-male jumper wires and connect the female end to the GND pin on the Line Detector. Connect the other end to the breadboard in the eighth column, fourth row (as shown here).

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STEP 4

Now take a third female-male jumper cable and connect it to the OUT pin of the Line Detector. Connect the other end to pin 25 on the EduKit Controller Board. This pin is used as the input pin to get a reading from the Line Detector. Note that the colours of your wires may not match the ones in the Worksheet diagram and it doesn’t matter which colour you use.

Add Sensors to Your Robot

STEP 5

Now it’s time for the Ultrasonic Sensor. Take it out of the its packaging and slot it gently into the breadboard. Make sure the GND pin is in a hole in the same column as the GND pins from Step 2 (as shown in this photo). The Echo, Trig and VCC pins should be in the breadboard holes to the right.

STEP 6

Take a good look at the resistors in the tutorial. You need a 33OΩ resistor. This should be orange-orange-brown-gold (or Orange, Orange, Black, Black, Brown). Bend both pins to form a U-shape and insert one end in same column as the Echo pin on the sensor. The other end goes into an unused column on the left.

BUILDING THE CIRCUIT

We’ve started putting together the circuit but now we need to use the resistors and remaining cables. The resistor is used with Echo because the sensor needs a +5v but the Raspberry Pi input only likes 3.3v. Be sure to check the resistors carefully. Now we’re going to use a 47OΩ resistor, which should be yellow-purple-brown (or Yellow, Violet, Black, Black, Brown). One end goes in the same column as the GND pin on the sensor, the other into the same column next 33OΩ resistor from Step 6.

With everything wired up, take the double-sided tape off the bottom of the breadboard and attach it to the top of your robot (with the sensor facing outwards). Use some of the double-sided tape that’s spare and connect the Line Detector to the bottom of your robot making sure the lens faces down.

Now take a jumper cable and place one end in the same column as the two resistors. Place the other end in Pin 18 of the EduKit Controller Board. Use a second jumper to connect the VCC connection to the EduKit Controller Board’s 5v socket. A third jumper connects the Trig column to Pin 17.

Now create the 5-distance.py code and place it in your EduKitRobotics directory. Use python3 5-distance.py to run the code and you will see distances appear on the screen. Place your hand in front of the sensor and watch how it adjusts accordingly. Now use the movement code with the sensor code to make your robot smart. Happy robotics.

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Turn an RC Toy into a Robot Stratos Botsaris shows us how to turn an old RC toy into a Spy Rover robot. This Raspberry Pi powered robot can be remote controlled from a smartphone, while you look through the on-board video camera. TOY CONTROL

This Spy Rover project turns an old remote control toy into a surveillance robot with the Raspberry Pi providing the brains. It’s a great way to get to grips with robotics and network communication.

STEP 1

We start with a Big Bargain King Force Excavator toy, although you can use any similar remote control device for the project. Our digger with tracks is ideal for robotics as it has simple controls and a track mechanism.

STEP 2

Stratos removed the top half of the robot so he just had the tracks to work with. The flat surface on the top of the robot provides a base for the rest of the components. The heart of the operation is a Raspberry Pi 1 Model B.

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STEP 3

The Raspberry Pi is placed inside a plastic case and an electronics breadboard is fitted on top. This is wired to the GPIO Pins using a breakout cable (using a device such as a Adafruit Pi T-Cobbler). This enables you to attach the rest of the electronics easily to the device.

STEP 4

Our Spy Rover wouldn’t be very effective without a camera. USB webcam is connected directly to the USB connection on the Raspberry Pi. An official Raspberry Pi Camera Module (raspberrypi. org/help/camera-module-setup) can be used instead, although it may not be as easy to position effectively.

Turn an RC Toy into a Robot

STEP 5

A generic L293D Stepper Motor Driver chip is placed into the breadboard. This is used to control two DC motors independently, which is handy because that is the right and left tracks of our remote control device. Learn more about using the L293D with this Adafruit tutorial: bit. ly/1n7p5IV.

STEP 6

The whole unit is powered using a Universal Battery Eliminator Circuit (UBEC). This provides 5V from an input of 5.5V-20V and is capable of supplying up to 3A. Then a battery box of 6 AA batteries provides enough voltage of 9V to the UBEC.

CONTROLLING THE SPY ROVER

The Spy Rover’s motors are controlled using the Raspberry Pi (via the L293D Stepper Motor Driver). You can set it up to act independently, but it makes a lot of sense to act as a remote control robot. It makes sense to use a controller with a screen so that you can see through the webcam. Rather than trying to attach a screen to a regular controller, it’s easier to add controls to a screen. Stratos built a controller app for Android.

STEP 1

The app enables Stratos to control the Spy Rover directly over a local network. The buttons on the bottom half send signals to the Raspberry Pi, which move the unit. The top half of the app streams the video from the webcam.

STEP 2


To move the Spy Rover forward the app sends a signal to the Raspberry Pi. To move forward, the motors turn clockwise and to move in reverse they turn anticlockwise. In case the rover needs to turn right, Stratos stops the right motor and make the left motor turn clockwise.

STEP 3

STEP 4 Streaming the video and building the Android app will be the biggest challenges. Stratos Botsaris has a YouTube channel where he explains how the Spy Rover works in more detail (bit.ly/1n7qKOO). The final result is a seriously detailed spy tool that allows you to remotely monitor any location where you have a network connection. BDM’s: Complete Raspberry Pi

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Using GitHub As you start to create advanced projects on the Raspberry Pi, you’ll need more advanced code. You could type it in by hand and often you’ll find code on developer’s websites but increasingly it’s being housed on Github. GETTING TO KNOW GIT

Git is online versioning software that enables you to store code online, download code, make changes and then integrate those changes. It enables many people to work together on software. Github (github.com) is a website that developers use to host links to the code.

STEP 1

Git enables you to clone code created by other developers on your Raspberry Pi. So it’s a vital tool to have on your Raspberry Pi. You install Git using APT. First enter sudo apt-get upgrade to get the latest package lists and sudo apt-get install git to install the latest version of Git.

STEP 2

Enter git –version to make sure it’s installed correctly. You should have the latest version installed (ours is 1.7.10.4). You can enter git –h to get quick help or man git to read the manual but Git is pretty complex at first so it’s better to follow our guide. We’re going to use the desktop to take a look at Github next, enter startx.

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STEP 3

Open the Epiphany web browser and enter github.com. Click Sign Up and create an account. Now open a terminal window and enter git config --global user.name “John Doe (replacing John Doe with your name). Next enter git config --global user.email [email protected] replacing the email address with the same one you used to sign up to Github.

STEP 4

Now we’re going to clone a project from Github to our computer. In the Epiphany web browser enter github.com/ lucyhattersley/fizzbuzz. This is a repository I’ve created on git that contains a program called FizzBuzz. A repository is like an online folder that contains the code. You will see links to the files contained in the project: README. md and fizzbuzz.py but don’t click these.

Using GitHub

In the bottom right of the Github window you will see a text box marked HTTPS clone URL and inside it is contained a URL. Click the text and press Control-A to select it all. Now right-click and choose Copy. Now open a terminal window and enter git clone and choose Edit > Paste to paste the HTTP address after the command.

STEP 5

Enter ls and you will see the Fizzbuzz directory in your home directory. Enter cd fizzbuzz to switch that directory and ls again to view the fizzbuzz.py and README.md files. FizzBuzz is a classic program that counts to 100 but on numbers devisable by 5 or 3 it prints Fizz or Buzz instead (or FizzBuzz if it’s devisable by both 5 and 3). Enter python fizzbuzz.py to run the code.

STEP 6

ADDING CODE TO GIT

Now that you know how to get clone code from Github on your Raspberry Pi, you might be wondering how to put your own code into Git. Git is a powerful and fairly complex piece of software but this will help you get started. We’re going to create a Python program that reverses a string and upload it to Git. Enter mkdir reverse_string and cd reverse_string. Then nano reverse_string.py and enter this code: import sys string = sys.argv[1] print string[::-1] Press Control-O and press Enter to save the code. Press Control-X to exit.

First we need a repository. Open Github (github.com) and click the green New Repository button. Enter reverse string in the Repository name field and select the Initialize this repository with a README option. Click Create repository to make the file. Next you need to copy the text from the HTTPs clone URL field as you did when cloning a website. Return to the command line and enter git remote add and use Edit > Paste to paste in the URL.

You can test the program by entering python reverse_ string “Hello World You should see dlorW olleH returned on the command line. We’re going to put his program on your Github but first it needs to be a Git folder, enter git init. This initialises the directory as a git repository. It creates a hidden file called .git to the folder; you can see this using ls –lah.

You’ve now linked the local directory to the Git repository and can sync changes from one place to another. Enter git add reverse_string.py to track the python file. Now enter git commit -m “First commit to tell Git you want to send (commit) the file to your Git space. Finally enter git push and enter your user and password to send the files. You’ll now see them on github.com. This is only a really rough introduction to Git. Head over to codeschool.com/courses/try-git to find an online course.

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Raspberry Pi Add-ons and Extras

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Raspberry Pi Add-ons and Extras INDEX

Raspberry Pi Add-ons and Extras HATs (Hardware Attached on Top) are an exciting addition to the Raspberry Pi hardware family. With them you’re able to extend the Pi’s electronics capabilities as well as add some extra, and very cool, features. Want to turn your Raspberry Pi into a drum machine? How about a sensor array, or even a high-powered amp? Whatever project you have in mind, there’s a HAT out there that can accommodate and improve it. We have several in this section to tantalise your imagination and find a use for the contents of your fruit bowl other than eating them; don’t worry, all will be revealed! Finally, we take a look at some common Raspberry Pi problems and how to tackle them should something appear to go wrong. After that, it’s purely down to you and your imagination; so get coding and dream big.


174 The Best HATs for Your Raspberry Pi

186 Raspberry Pi Screens and Displays

180 Raspberry Pi Kits

188 Android Apps for Pi Users

182 Raspberry Pi Cases

190 Essential Software

184 Raspberry Pi Robots

192 Common Raspberry Pi Problems


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The Best HATs for Your Raspberry Pi HATs (Hardware Attached on Top) are a great way to expand your Raspberry Pi’s horizons. These custom boards fit into the GPIO pins and sit on top of the Raspberry Pi, offering a range of quirky, unique and interesting hardware options. SETTING UP A HAT

You shouldn’t have any trouble setting up a Rasbperry Pi HAT. The hardware is designed to work as soon as you connect it to the GPIO pins. But from then you’ll have a whole range of new hardware options available; check the documentation on each maker’s website.

SENSE HAT

The first HAT you should got out an buy is this one, the SENSE HAT. This board was developed as part of the Astro Pi project, and was used by Tim Peake aboard the International Space Station (ISS). It features an 8x8 RGB LED display, joystick, gyroscope, accelerometer and magnetometer. It’s also got a bunch of sensors to measure pressure, humidity, depth and altitude. So you get a lot for your money, and there are all kinds of quirky things you can do with a motion sensing HAT with a joystick and interactive RGB display. The best thing about the Sense HAT is that there are lots of tutorials already waiting for you at astro-pi.org/resources/. These have been created by thousands of other enthusiasts following Peake’s space mission, and you can even reproduce the same experiments at home that Peake is running in space. It’s a really fun device and you’ll really get your money’s worth.

PRICE: £23 / €25.99 174

More info: raspberrypi.org/products/sense-hat/


ADAFRUIT SERVO HAT

The Raspberry Pi is a very capable board, but one thing it kinda sucks at is controlling servos (RC servomechanisms). This is because servos need a repetitive pulse signal. You can create this by switching a GPIO pin on and off in Raspbian, but it’s far too easy to get the timings wrong (or for the OS to mess up while multitasking). If you want to build robots, you’ll need to control servos and the best way to do this is using an additional board dedicated to just that. The Adafruit Servo HAT is a great option because it combines the pulse timing mechanism with a power supply for the servo motors. You can control up to 16 different servos from one Servo HAT (and stack them up to control up to 96 different motors). On top of this, Adafruit has built a comprehensive Python library for servo control; so it’s really easy to start controlling your robots.

PRICE: £16 / €18.08

More info: modmypi.com

The Best HATs for Your Raspberry Pi

DRUM HAT Turn your Raspberry Pi into a portable drum machine with this innovative Drum HAT. Not wanting to be outdone by it’s older brother (the Piano Hat, left) this uses the same capacitive touch sensor technology to recreate a drum machine. There are eight sensitive drum pads on the Drum HAT, each one with an LED light. Tap a drum pad to make the beat. The corresponding Python software library is used to create all kinds of example sounds and drum machines. You can use the USB out on your Raspberry Pi to send MIDI commands to a hardware synth too. The DRUM Hat is designed to work alongside the Piano HAT and using the Black HAT Hack3r (above) allows you to use both devices together. So with all three HATs you can recreate a full synth studio right on your Raspberry Pi. That’s pretty cool. More info: shop.pimoroni.com/products/drum-hat

PRICE: £12 / €13.56 HATs are great, but one shortfall of most of them is that they take over all your GPIO pins. This is a bind because it means you can’t use multiple HATs at once, or combine a HAT with your own electronic circuit. The Black HAT Hack3r is a nifty HAT that allows you to connect two HATs together in a single project, or you can add a HAT and use the spare GPIO pins to make your own project. The Black HAT Hack3r was created for HAT development and debugging, so if you’re interested in making your own HATs then this is the device to get. Unlike most HATs this doesn’t fit directly on top of the Raspberry Pi, instead it uses a 40 pin GPIO ribbon cable (supplied) to create a separate board to the side of the Raspberry Pi. This board does have four mounting holes to screw in a second HAT, along with a second set of GPIO pins (all clearly labelled). There are some great tutorials online showing what you can do with a Black HAT Hack3r, such as the one that combines a Skywriter HAT with a Unicorn HAT display.

BLACK HAT HACK3R

Fancy yourself a budding Bach? This might not be a full-sized keyboard, but it’s a cracking HAT that turns your Raspberry Pi into a synth complete with a single octave of black and white piano keys. We think this is one of the coolest Rasbperry Pi HATs around, and works perfectly. It features 16 touch-sensitive buttons, including a full octave of 13 keys. This is combined with a full Python library of programs and documentation. You can, if you want, use the keyboard to control other things (such as servos). Or you can create a variety of synths, play WAV files and use MIDI to play music. On the right of the keyboard are octave up and down buttons, so you can play the full range from a keyboard. There are LEDs on each button, which can be used to create follow-along-tracks. If you’re into digital music then the Piano HAT is glorious way to explore the world of synths.

PIANO HAT

PRICE: £15 / €16.95 www.bdmpublications.com

More info: shop.pimoroni.com/products/piano-hat

PRICE: £10 / €11.30

More info: shop.pimoroni.com/products/black-hat-hacker


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One of the real delights of using a Raspberry Pi is the direct access to the GPIO pins. Most people use a Raspberry Pi with a breadboard for testing out circuits, and a breakout cable provides a bit of safety to separate the Rasbperry Pi from external voltage. The explorer HAT combines all of this (and a bit more) into a single board that sits on top of your Raspberry Pi. It has buffered 5v inputs and outputs so you don’t have to worry about spikes and a small breadboad for your components. It also has four capacitive touch pads, four crocodile clip pads and four coloured LEDs. So you can create a lot of projects without needing additional parts. There’s a PRO version that also has four analogue inputs (a feature missing on the Raspberry Pi) and H-bridge motor drivers. It’s a very popular choice for enthusiasts looking for a small, but effective, prototyping kit.

EXPLORER HAT PRO

PRICE: £18 / €20.34

More info: shop.pimoroni.com/products/explorer-hat

HIFIBERRY AMP+

The Raspberry Pi does an lot out of the box, but it’s sound quality leaves a bit to be desired (it’s not built for high fidelity sound). The HiFiBerry is a sound card designed for the Raspberry Pi. There are three different versions of the HiFiBerry: the DAC+ is designed to improve the sound of the Raspberry Pi with a digitalto-analog converter; the Digit is a high-quality S/PDFI output board designed with a digital output; meanwhile the Amp+ (pictured below) is a digital-to-analog converter that directly drives 25W speakers. We think the Amp+ is ideal for audio enthusiasts looking to turn a Raspberry Pi into an amplifier and use it to play digital audio. It runs at 44.1kHz and 48kHz sample rates and has a fully digital sound path – the audio quality is amazing for such a small device. It is capable of driving 4 Ohm speakers as well, perfect for parties.

PRICE: £39 / €44.07

More info: hifiberry.com/ampplus/

DISPLAY-O-TRON 3000 The one thing about the Raspberry Pi, is that you have to hook it up to a monitor. This is great when you’re building a project, but sometimes you want to take your Raspberry Pi out into the world and still have it communicate information back. This is where the Display-O-Tron 3000 steps up: it’s a capable 3x16 character display with three RGB backlights. While it isn’t a full monitor (such as the TFT Display), it allows the Raspberry Pi to communicate information without dragging down the battery. It also has a 5-way joystick that can be used to control the Raspberry Pi when it’s away from a keyboard and mouse. There’s also a 9 LED bargraph running along the top, that can be used to display information such as volume levels or CPU usage. You write text to the Display-O-Tron 3000’s screen using the Python lcd module (available from github.com/pimoroni/ dot3k.) There are lots of examples and projects to try out, so you can go from writing text to the display all the way up to building interactive menus and even games. More info: shop.pimoroni.com/products/ displayotron-3000

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PRICE: £18 / €20.34


SKYWRITER Skywriter is a quirky HAT that adds 3D gesture sensing to the Raspberry Pi. You wave your hand above the HAT, and it can detect exactly where your fingers are pointing. Skywriter HAT works by creating an electric near field just above the Raspberry Pi. This detects x,y,z movement to determine the exact position of the hand above it. The position detection enables the Raspberry Pi to determine swipes, taps and other gestures made in mid-air. It’s great fun to use, and there are simple projects such as creating Star Wars these are not the droids you’re looking for interactions. But it’s surprisingly detailed, and soon you can create virtual control devices that react to swipes and taps to control the screen. Check out this video of a Skywriter HAT combined with a Unicorn HAT (vine.co/v/OXVehbD6T6q) to see more advanced visual displays. More info: pimoroni.com/products/skywriter-hat

PRICE: £16 / €18.08

PaPiRus is a HAT under development with an interesting function. It gives the Raspberry Pi a small electronic-ink display (the kind you find inside e-book readers like the Amazon Kindle). You can use the Raspberry Pi as an e-reader, and it’s good for investigating how e-readers work, but the real advantage is the incredibly low power requirement of an electronic display. E-paper displays and single board computers are a match made in heaven, says Aaron Shaw, the creator of PaPiRus, because together they use a very small amount of power but still bring extremely capable displays to your project. Three different screen sizes are available: 1.4-inch, 2.0-inch and 2.7-inch. It’s a great HAT for outdoor projects (it works in direct sunlight) that will require long-battery life.

PaPiRus

Drones are some of the most exciting things to build with a Raspberry Pi, but you need to be careful with spinning blades whirling around the air. Teaching a Raspberry Pi to fly is no mean feat, and it needs to know where it is, which way it is facing, how level it is and a whole host of other information. On top of this you need to finely control the motors to correct your flight path. The Navio2 is a linux autopilot HAT for the Raspberry Pi. It runs the APM (ArduPilot) flight stack that can opererate in different flight modes (manual, stabilize, follow-me and auto). The HAT also a gyroscope, accelerometer, magnetometer, barometer and GPS sensors so it can tell exactly where it is. With 14 PWM servo outputs it can control the most complex of flight devices, including classic quadcopters, blimps and drone aircraft. There is a lot of supported code and many user projects show you how to get started. It’s a bit pricy, but essential if you want to get your drone project off the ground.

NAVIO2 AUTOPILOT

PRICE: £30-65 / €34-72 More info: pi-supply.com/product/papirus-epaper-eink-screen-hat-for-raspberry-pi/


PRICE: £113 / €127.69

More info: emlid.com


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The Parallax Propeller is a very popular microcontroller used to control all kinds of robotics projects. Normally you’d attach the Propeller to a circuit board (or breadboard) but the Propeller HAT combines a 8-core Propeller P8X32A-Q44 microcontroller with HAT architecture, so you can just slot it on top of your Raspberry Pi. Once attached, you can run servos, control robotics, or create home automation devices. As a bonus there’s a breadboard on top so you can create test circuits and create early prototypes. There are also female headers for Propeller I/O access. Take a look at Pimoroni’s projects page (learn. pimoroni.com/propeller-hat) if you want to see more about what kinds of projects are available. Take note that you’ll need to do some soldering to put the HAT together.

PROPELLER HAT

When you’re building test projects, you generally don’t mind if the power cuts out. But once you start building something important, the idea of a power cut shorting your device can be a real concern. UPS Pico is an advanced uninterruptible power supply for the Raspberry Pi A+/B+ and Raspberry Pi 2, that adds a wealth of innovative power back-up functionality and development features to the innovative microcomputer. If there is a power failure, the UPS Pico will automatically shut down your Raspberry Pi and will automatically monitor the power situation. Once the power is restored it will reboot your Raspberry Pi. An optical 3000mAH battery version can keep a Raspberry Pi running for eight hours before shutting it safely down, long enough to keep running through most power cuts.

UPS PICO

PRICE: £22 / €24.86 PRICE: £15 / €16.95

More info: parallax.com/product/32230

More info: modmypi.com/raspberry-pi/breakout-boards/pi-modules/ups-pico

UNICORN We love the Unicorn HAT, it’s one of the most fun pieces of hardware you can buy. The whole surface is covered in LEDs that can light up in a rainbow of colours. The surface sports a matrix of 8 x 8 LED lights (making 64 lights in total) that are used to create a light aurora. It’s great fun to play with, and projects include mood lighting, persistence of vision effects, status indications or disco lights. We think this is one of the best Raspberry Pi HATs you can buy to start with, because it’s easy to program and there are some great example projects available. It also comes with a stack of programs and examples, all available on GitHub (github.com/pimoroni/ unicorn-hat). Projects include clocks, sparkles, matrix effects and pixel painting via a web browser. There’s also substantial documentation on how to use the Python modules and program the Unicorn HAT. It’s hard to get an impression of how cool the Unicorn HAT is from a still photograph, so take time to check out this video: vimeo.com/105482682. More info: shop.pimoroni.com/products/unicorn-hat

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PRICE: £24 / €27.12


If you’re looking for a full display for your Raspberry Pi, then the Adafruit Pi TFT 2.4 is one of the best to get. It features a 2.4-inch TFT screen with 320x240 16-bit colour with a resistive touch overlay. So you can build a touch-screen display for your Raspberry Pi project. The HAT uses the high speed SPI interface on the Pi and can use the mini display as a console, X window port, displaying images or video. The HAT uses the hardware SPI pins (SCK, MOSI, MISO, CE0, CE1) as well as GPIO 25 and 24. All other GPIO are unused and a right-angle connector allows you to connect a GPIO cable and access the remaining pins, so it provides a touchscreen interface for other projects. A custom kernel package enables installation in Raspbian with just a few commands. A range of tutorials walks you through using the HAT.

ADAFRUIT PI TFT 2.4

PRICE: £24.50 / €27.69

More info: www.adafruit.com/products/2455

ADAFRUIT CAPACITIVE

This HAT is pure fun. Capacitive touch sensing works by detecting when a person (or animal) has touched one of the sensor electrodes. Capacitive touch sensing used for stuff like touch-reactive tablets and phones, as well as control panels for appliances, which is where you may have used it before. This shield allows you to create electronics that can react to human touch, with up to 12 individual sensors. There are some really great example projects, such as this fruit keyboard that plays audio as you tap the fruits. You’ll need to do some light through-hole soldering to attach the headers onto the shield circuit board, but its easy to do with basic soldering tools like a soldering iron and rosin core electronics solder. It’s a hugely entertaining project.

PRICE: £13 / €14.69

More info: www.adafruit.com/products/2024

PI-DAC+ The Pi-DAC+ audio card delivers full HD audio capability on your Raspberry Pi, it’s the audio enthusiasts dream. It clips on top of your Raspberry Pi and uses the Raspberry Pi’s I2S digital audio signal (this draws much less power than using the USB out). Output from the Pi-DAC+ is by industry standard Phono connectors (variable to 2v RMS) allowing easy connection to an existing Hi-Fi or sound system, headphone connection is by standard 3.5mm jack socket. The Pi-DAC+ also provides access to the majority of the Raspberry Pi I/O signals allowing flexibility to your project and easy connection to our other IQaudIO products. This allows for additional peripherals (buttons, LEDs, LCDs, rotary encoders, IR sensors or similar) to be added. Audio pin headers are also included to connect to the Full-HD 2x20w Class D Pi-AMP+. You cn use Volumio, RuneAudio, SqueezePlug, PiCorePlayer, PiMusicBox, AirPlaySync, MDP or raw audio files in Linux to play audio through the Pi-DAC+. And you can set up services like Spotify to work with the device. More info: shop.pimoroni.com/products/pi-dac


PRICE: £31.50 / €35.60


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Raspberry Pi Kits It is quite simple to research all of the parts you need for a particular project, such as building a media centre. Checking different sites for the best prices and then waiting for everything to be delivered. However, it is often much easier and often no more expensive to just buy a kit. With the added bonus that kits may sometimes include bespoke parts, such as cases and cabinets. CHOOSING A KIT

The Raspberry Pi kit you choose will depend on your planned use for the device but if you are completely new to the RPi, choosing a basic kit is a great way to learn how things work.

RASPBERRY PI 3 MEDIA CENTRE KIT

RETRO GAMING KIT PRICE: £59.99 / €67.79

The PiHut’s Supercharged Raspberry Pi 3 Media Centre kit includes everything you need to get going right out of the box. The kit includes the latest Raspberry Pi 3 Model B (64bit Quad Core, 1GB RAM), an 8GB or 16GB Sandisk Ultra Class 10 MicroSD (preimaged with Kodi), an official Raspberry Pi 5.1V 2.5A International power supply (for UK, EU, USA and AUS), a classy black Raspberry Pi 3 Case, a high quality 2M HDMI cable and a 2M Ethernet cable. With complete instructions, all you need to do is just put everything together and hook it up to your TV or an HDMI monitor, and away you go.

PRICE: £50.00 / €56.50 180


It’s now easier than ever to transform your Raspberry Pi into an all-in-one retro gaming console thanks to the RetroPie project. ModMyPi’s Retro Gaming Kit, which includes the Raspberry Pi 3 Model B, has everything you need to get started on your Raspberry Pi retro gaming console. The kit includes everything you could want. There’s the game controller, case and keyboard, the heatsinks (gaming on your Raspberry Pi can increase the heat generated and heatsinks help with this) and cables you need along with a detailed online guide, taking you through the process step-by-step.

Raspberry Pi Kits

PICADE – RASPBERRY PI ARCADE MACHINE PRICE: £180.00 / €203.40 A stylish, retro and fun arcade cabinet for your Raspberry Pi, the Picade comes in kit form for you to build at home. All parts, panels and components are included, you just need to supply the Raspberry Pi and power adapter. Unlike some arcade cabinet kits this one includes panels that are powder coated in black so the end result feels like a finished, quality product. The chassis makes a great sounding board for the speakers. Picade is the ideal desktop arcade cabinet and you really have to see it to believe it. Total build time is around one to two hours and full instructions are available online. The only tools you’ll need are a crosshead (pozi) screwdriver and a small flathead for the Picade PCB screw terminals.

SUPREME KIT – RASPBERRY PI 3 (MODEL B) ModMyPi’s Raspberry Pi Supreme Kit, including Raspberry Pi 3 Model B, comes with everything contained in the Starter Kit with the addition of input hardware. The developers of the kit have compatibility tested all components and only selected the very best manufacturer guaranteed, high quality parts available. You won’t find a better kit at a better price and all the kits are fully customisable from the huge range of Raspberry Pi accessories, cases and cable colours. They also stock UK, US, AUS and EU variants of the majority of the components so there’s no need to worry if you’re ordering internationally.

PRICE: £50.99 / €57.17 FRANZIS RASPBERRY PI FOR KIDS KIT PRICE: £39.99 / €45.19 With a 128 page booklet full of colourful and easy to follow instructions, you can learn and create with your Raspberry Pi. Compatible with the Raspberry Pi and Raspberry Pi 2 (sold separately), this kit guides you through setting up, programming and using your Raspberry Pi. Experiment with clay as an input, becoming the controller in anything from lighting a bulb to creating a gamepad. Explore circuit building with components like LEDs and resistors. There’s no need to solder the components, as they slot into the two breadboards that are supplied. You can even become part of the circuit, as it works by needing a complete loop for electricity to travel through and the model clay supplied has enough conductivity for you to close the circuit by touching them.

KEYES 34 SENSOR KIT The Keyes 34 piece sensor experiment kit adds an enormous amount of variety and additional fun to every maker’s toolbox. The kit features a range of assorted sensors, detectors, switches and emitters. If you’ve ever fancied wiring up a and experimenting with a host of different sensors, then this is the kit for you. The kit is suitable for use with most microcontrollers including Raspberry Pi and there’s a large amount of information available, including example code. Each sensor is preassembled, so there’s no soldering required and the kit comes in a neat compartmented clip together plastic box, so you can order and store all the sensors safely. There’s even a neat cheat sheet included in every box that has the name and picture reference for each sensor.

PRICE: £33.99 / €38.41 www.bdmpublications.com


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Raspberry Pi Cases The case you choose for your Raspberry Pi can depend on what your final use will be. A media streaming Raspberry Pi, which will probably sit next to your TV, may look better in a sleek, black case. A Pi used for a retro games console might look better in a more colourful or exciting one. Then there are the specialised cases, used for specific Raspberry Pi projects. Let’s take a look at some of the best examples available. CHOOSING THE RIGHT CASE

There are literally thousands of cases available for the Raspberry Pi, and choosing the right one can make a difference as to how easy it is to complete your planned project. Think carefully before you buy.

PIBOW RAINBOW

PI-BLOX LEGO-STYLE CASE PRICE: £5.99 / €6.77

Pibow Rainbow is a sleek, durable and attractive case crafted out of eight unique coloured layers with a transparent top and base that will leave your beautiful Raspberry Pi visible inside. Each layer is laser-cut from colourful high quality cast acrylic and once stacked they securely contain a Raspberry Pi 2 or Model B+ while leaving the primary ports, including the camera port, accessible. Weighing only 92 grams the case is lightweight and ideal for mounting to any surface. No tools are required for assembly or disassembly.

PRICE: £13 / €14 182


The Pi-Blox Lego Compatible Case for Raspberry Pi and camera is a great addition to your Raspberry Pi arsenal. This enclosure is not only a good way of protecting your Raspberry Pi board but also fully compatible with the Lego building block system. It stacks top and bottom (standard Lego fixings on base and lid) and features all the necessary openings for connectors and ports; and it includes mounts for the Pi camera, which can be fitted inside the case with holes in the lid for the camera lens and flash.

Raspberry Pi Cases

FLIRC CASE PRICE: £15 / €17

PREMIUM RASPBERRY PI ZERO CASE This slim little Pi Zero case consists of a three part clip together construction, with a Micro SD card cover and embossed Raspberry Pi Foundation logo that acts as a ventilation point for heat extraction. The case features a top and bottom GPIO cut out, which can easily be removed using a sharp instrument, or left in situ if the GPIO is not required. There are also two M3 mounting holes on the back of the case, so you can effortlessly mount your Pi Zero where it’s required e.g. your belt, dog, table or wall, and two internal microSD card slots to store you spare OS images.

The Flirc Raspberry Pi case was designed to not only be functional for your Raspberry Pi but also really attractive. It’s made of a beautiful aluminium core sandwiched between two black, soft touch shells that feel great in your hands. Once it’s out of your hands, it’s deserves to be proudly on display running your favourite media centre software. In addition to the built-in heatsink, small ventilation slots on the bottom help keep the Raspberry Pi cool. GPIO pins are accessible through the slot on the bottom of the case and there is no need to dismantle it to get to the SD card.

ORBITAL CASE FOR RASPBERRY PI This beautiful round design is perfect for your desk or for smart home solutions. The Orbital Case for Raspberry Pi is completely designed and produced in Germany. All connections are routed on to one side, so you can say goodbye to tangled cables. It should fit perfectly on your desk. The Orbital Case consists of a robust and impact resistant plastic material. Threaded metal inserts on the cover ensure wear-free use even when the case is opened frequently. The Orbital Case is compatible with all Raspberry Pi boards.


PRICE: £14.49 / €5.65 Made of ultra-durable, super glossy polycarbonate, the Adafruit case is both good looking and tough enough to toss into your bag or toolbox. It has slim openings for all your cables, an easy-to-remove bevelled slot for your Micro SD card, slots for both your Pi Camera and upcoming Display and a space for your GPIO cable to extend out from the Pi. The Pi snaps into the base and the lid fits snugly onto the top. If you want to break out your Pi you can use your case without the lid and add hats to your B+ with ease.

ADAFRUIT RASPBERRY PI CASE PRICE: £14 / €15 BDM’s: Complete Raspberry Pi

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Raspberry Pi Robots Robots for the Raspberry Pi usually come in one of three types: self-build robots, robot chassis and full robot kits. Here we will be looking at some of the best of the last two types, chassis and kits but there is nothing to stop you being super creative and building your own from random parts. ROBOTICS FOR BEGINNERS

Buying a robot kit for the Raspberry Pi can be quite expensive, but it is undeniably the best way to really understand just how adaptable and powerful this clever little device can be.

MAKEBLOCK 90040 ULTIMATE ROBOT KIT V2 Based on the Makeblock robot building platform, the Ultimate 2.0 is a flagship robot kit with a rich features list and strong compatibility. Whether you are an enthusiast of Raspberry Pi or Arduino, a mechanical or electronics engineer, a teacher or a student, it lets you learn mechanical structures, electronic modules and programming skills with ease. Learn to build and control Ultimate 2.0 and enjoy the fun of creating. This kit allows you to build at least 10 different robots.

PRICE: £269.00 / €303.97 184


MEARM - POCKET SIZED ROBOT ARM The MeArm comes as a flat pack robot arm kit, that you can build with nothing but a screwdriver and enthusiasm. It is a great kit to get you started in the world of programming, electronics, robotics and engineering. The full kit contains everything you need to get started, including a MeArm robot arm kit, Brains Board for programming, Joystick controller and battery case (batteries must be bought separately). The MeArm also works with Beaglebone Black, Sparkcore, Espruino and many more systems.

PRICE: £33.00 / €37.29

Raspberry Pi Robots

MINI ROBOTSHOP ROVER

PRICE: £18.67 / €21.10

GOPIGO STARTER KIT The GoPiGo Stater Kit is a complete kit to build your own robot car. GoPiGo works at the level you’re at, whether you are a parent looking for a smart, fun weekend project to do with your kids, a teacher looking for a way to increase engagement in your science course or a grad student in need of a platform for your robotics research that requires mobility. Various upgrades are available to buy, including servo kits. The GoPiGo is stacked on top of the Raspberry Pi without the need for any other connections.

The Mini RobotShop Rover Chassis Kit is a small, inexpensive tracked platform onto which you can mount a Raspberry Pi. The frame is made out of laser-cut Lexan parts and the Tamiya Twin Motor Gear Box, which must be assembled, and Tamiya Track and Sprocket Kits are used for propulsion. Mounting hardware is included. There is a 30mm wide x 6mm high gap in the top support plate specifically for a RobotShop 3.7V, 1000mAh LiPo battery and front mounting slots for general use.

CAMJAM EDUKIT #3 The CamJam EduKit #3 is focused on robotics and contains almost everything you need to create your very own Raspberry Pi-powered robot. All you need to do is add your own chassis, Raspberry Pi (any model) and batteries. Then, follow the worksheets to make your own motorised buggy. The kit includes motors, wheels, a small breadboard and battery box. Add the sensors that are included and you will soon be detecting objects in front of your robot and following line courses.


PRICE: £199.00 / €224.87 Mirobot is a build-it-yourself Wi-Fi drawing robot kit that’s designed to help children learn about technology, engineering and programming. Mirobot is a Wi-Fi robot which means it’s really easy to connect to all of your existing devices, whether it’s a laptop, tablet or even a phone. Everything you need to get it drawing is builtin but once it’s on your Wi-Fi network you’ll be able to use a wide range of apps, for a wide range of ages, to help you make it do new things.

MIROBOT V2

PRICE: £60.00 / €67.80 BDM’s: Complete Raspberry Pi

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Raspberry Pi Screens and Displays It is very easy to connect your Raspberry Pi to a standard TV or computer monitor using an HDMI cable but sometimes your project might need a different type of screen. Large and small touchscreens, e-ink screens and even LED readout displays, are all available for the Raspberry Pi at a wide range of prices. DO YOU NEED A SCREEN?

Not every Raspberry Pi project will need a display, but even the simple ones can make it easier to understand what is going on inside the hardware when working on projects.

ADAFRUIT PITFT 2.8 INCH TOUCHSCREEN

PAPIRUS EPAPER / EINK SCREEN ePaper is a display technology that mimics the appearance of ink on paper. Unlike conventional displays, ePaper reflects light, just like ordinary paper, and is capable of holding text and images indefinitely, even without electricity. Because of this, ePaper displays and single board computers or microcontrollers are a match made in heaven, as together they use a very small amount of power whilst still bringing a display to your project. This ePaper display is designed as a HAT and has a 2.7 inch screen size.

The Adafruit PiTFT is one of the smallest but one of the most useful screens for the Raspberry Pi. It features a 2.8 inch display with 320x240 16-bit colour pixels and a resistive touch overlay. The plate uses the high speed SPI interface on the Pi and can use the mini display as a console, X window port, displaying images or video. Best of all it plugs right in on top Uses the hardware SPI pins (SCK, MOSI, MISO, CE0, CE1) as well as GPIO #25 and #24. All other GPIO are unused.

PRICE: £34.99 / €39.54

PRICE: £30.00 / €33.90

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Raspberry Pi Screens and Displays

4DPI-35-II TFT LCD COLOUR DISPLAY Add a primary touch screen to your Raspberry Pi quickly and easily with a display from 4D Systems. Available in two sizes, 3.2 inch (RS 909-4105) and 3.5 inch (RS 909-4108), both of which attach via the 40 way header. Power for the screen is supplied from the Raspberry Pi so there is no need for an additional power supply. Installation and set up with your Raspberry Pi can be completed in just a few minutes using the software download available from the 4D Systems website.

ADAFRUIT RGB 16X2 LCD+KEYPAD KIT This Pi plate is perfect for when you want to build a standalone project with its own user interface. The 4 directional buttons plus select button allows basic control without having to attach a bulky computer. The plate is designed for both Revision 1 and Revision 2 Raspberry Pis. It uses the I2C (SDA/SCL) pins. It also has a special extra-tall 26-pin header so the plate sits above the USB and Ethernet jacks. This product comes as a kit. Included is a high quality PCB and all the components (buttons, header etc.) and a 16x2 Character RGB positive LCD. Assembly is easy, even if you’ve never soldered before and can be completed in 30 minutes.

PRICE: £59.99 / €67.79 OFFICIAL PI 7-INCH TOUCH DISPLAY Turn your Raspberry Pi into a touch screen tablet, infotainment system, or stand-alone device. Truly Interactive, the latest software drivers will support a virtual ‘on screen’ keyboard, so there is no need to plug in a keyboard and mouse. Make your own ‘Internet of Things’ (IoT) device including a visual display. Simply connect your Raspberry Pi, develop a Python script to interact with the display and you’re ready to create your own home automation devices with touch screen capability.


PRICE: £24.99 / €28.24 ADAFRUIT 10.1IN IPS DISPLAY This is a great little HDMI television with incredibly high resolution and built in 3.5W stereo speakers. The display is very easy to use. Simply connect a 9 to 12VDC adapter to the 2.1mm centre-positive DC jack (not included) then connect a digital video source to one of the ports. There are some buttons on the front that let you enter a menu system for adjusting brightness, colour and contrast. It auto-detects which input you have and switches to that one or you can ‘select’ from the menu which to display. It comes with a basic stand and there are two mounting holes on the back.

PRICE: £199.99 / €225.99 BDM’s: Complete Raspberry Pi

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Android Apps for Pi Users When you are working with a Raspberry Pi, it isn’t always easy to switch between a computer for the set up and coding tools, and the Pi. Luckily, there are loads of brilliant Raspberry Pi compatible tools for Android, letting you control many aspects of your projects from the palm of your hand. From network scanners to dashboard creators, these apps are definitely worth checking out if you are seriously in to RPi. MAKING USE OF APPS

There are lots of apps available for smartphones that can help you when working with a Raspberry Pi, and more are being released all the time. Check out the app store for your device to see more.

RPiREF

APP AWARE

RPiREF for Raspberry Pi is an easy and quick way of checking the Pin-out and GPIO references of Pi’s P1, P5, P6 and J8 headers. This information is already available in a number of forms but having it available on your Android smartphone or tablet is useful when you are experimenting or discussing Pi ideas with friends. The app also contains some simple tips for identifying the different models. The Zoom button on the GPIO header page allows you to set a zoom level so you can see the diagram in a size that suits your device and eye-sight. Just like the Model setting this is remembered between sessions.

There are countless apps available on the Google Play Store relating to the Raspberry Pi, from connecting to it and controlling it, to creating virtual electronic components to fit to the GPIO. However, whilst many are superbly written apps, others fall well below par.

The app provides reference information and covers Model A and B: Pin numbering of the 26pin GPIO Header P1, Pin numbering of the P5 Header on Rev 2 boards, P6 reset header, 3.3V, 5V and ground pins, Status LEDs and Audio Jack; also Pi 3, Pi 2, A+, B+ and Pi Zero: Pin numbering of the 40-pin GPIO Header J8, RUN reset header, 3.3V, 5V and ground pins, Status LEDs, Audio Jack.

PRICE: Free 188


Type: Reference

There are many apps that simply don’t work, no matter how much you try and use them to communicate with the Raspberry Pi. Others do connect but fail to transfer data or drop the connection once you start to use them. Others still are just too out of date for the more recent models of Pi and Android versions available. Then, there are some that can, inadvertently, cause software conflicts and damage to either the Raspberry Pi, the operating system or even the device you’re using. Whilst the latter are few and far between, it’s worth mentioning that not all apps are created equally. Therefore we recommend you thoroughly read through the app’s comments from other users, as well as it’s Additional Information section to familiarise yourself with how it works. Spending a bit of time researching an app can save you a lot of potential headaches in the future.

PRICE: Free

Type: Reference

Android Apps for Pi Users

JUICESSH

CAYENNE

JuiceSSH is an all in one terminal client for Android including SSH, Local Shell, Mosh and Telnet support. Featuring a modern holo UI making JuiceSSH a pleasure to use and the best possible experience for SSH on the go. Keep all of your connections and settings in sync between all of your devices. All synchronisation is encrypted with industry standard AES-256 encryption.

Once you catch the Raspberry Pi bug and start attempting more advanced projects, a tool like Cayenne will quickly become an essential. Start your next Raspberry Pi project or prototype from your phone with Cayenne IoT project builder. Download Cayenne straight to your Android smartphone and start your project in a fraction of the time. You can add, manage and control all sorts of sensors and actuators from your phone’s dashboard with drag and drop widgets. You can even customise the look of your projects with a fully flexible dashboard.

There is a Pro version available for a small fee but even the free version has a massive feature list, including: Full colour terminal and SSH client with xterm, ncurses and UTF-8 support; Popup keyboard with special characters (Ctrl, alt, tab etc.); External keyboard support (Bluetooth and USB-OTG); Telnet and local Android terminal support; Third party and community plugin support; Save and Share SSH transcripts to Dropbox/Evernote/Email & SD card; Seamlessly connect ‘via’ other SSH connections with one click; and Key import, export and generation tools.

PRICE: Free

Type: Communications

Even more impressive features include the ability to create custom projects with mix-and-match widgets from multiple Raspberry Pis and Arduinos and all on a single dashboard. It discovers your Pis and sets them up to be managed remotely in your network. Discover different ways to visualise data and control your connected hardware, and automate your project with easy to create if/then statements. The Cayenne app only currently works on Android phones, although tablet support is promised soon.

PRICE: Free

Type: Development Tool

MAKING YOUR OWN PI APPS If you find that the Google Play Store’s selection of Raspberry Pi apps is limiting, and a little dull, then why not start to create your own? Proper app development does require a good level of programming knowledge; however; you can get up and running relatively quickly thanks to Android Studio. Android Studio is the official IDE for Android, a quick and easy to use tool that’s designed to allow you to build apps for any Android device. With it you can code edit, debug and test performance; then quickly deploy the app for further testing. It even comes with a fast and feature-rich emulator to help you fine-tune your code. There are code templates, GitHub integration, intelligent code editing and a vast collection of resources to apply to your own custom app. You will need to learn how to get to grips with the interface and programming logic behind the development kit first. Thankfully, there’s a handy Getting Started guide found on the Android Developer pages at www.developer. android.com/training/index.html. Have fun, and let your imagination loose.

PRICE: Free www.bdmpublications.com

Type: Development Tool


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Essential Software Both the set up and smooth running of your Raspberry Pi requires several pieces of essential software, from SD card formatting tools to the NOOBS installation software. Any piece of software needed to complete one of our guides or projects will be mentioned on the relevant page but it can be frustrating to get halfway through a process and then have to pause to find something you need. Our essential software guide will allow you to more easily and quickly gather the tools you need for many Raspberry Pi processes. THE RASPBERRY PI SOFTWARE KIT

The software mentioned here is probably the bare minimum you will need to get the most from your Raspberry Pi. Specialised software might be needed for more specialised projects.

GPARTED

Gparted (GNOME Partition Editor) is a an official GNOME partition editing application alongside Disks. GParted is used for creating, deleting, resizing, moving, checking and copying disk partitions and their file systems. This is useful for creating space for new operating systems, reorganising disk usage, copying data residing on hard disks and mirroring one partition with another (disk imaging).

NOOBS (NEW OUT OF THE BOX SOFTWARE) If you are planning on using Raspbian OS with your Raspberry Pi, you will probably want to have NOOBS in your software library, although you can install Raspbian without using NOOBS. There are two versions of NOOBS. - NOOBS is an easy operating system installer which contains Raspbian. It also provides a selection of alternative operating systems which are then downloaded from the Internet and installed. You will need to be able to connect your Raspberry Pi to the Internet. - NOOBS Lite contains the same operating system installer but without Raspbian preloaded. It provides the same operating system selection menu allowing Raspbian and other images to be downloaded and installed.

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WIN32 DISKIMAGER

This program is designed to write a raw disk image to a removable device; or backup a removable device to a raw image file. It is very useful for embedded development, namely Arm development projects (Android, Ubuntu on Arm, Raspberry Pi, etc.). The OS used by Raspberry Pi, whichever you choose to use, is stored on and accessed from the removable MicroSD card, so you will need this software to change the OS image you want to use. You will need some way, such as a card reader, to connect your SD card to your computer before you can use this software.

Essential Software

WINSCP There might be times, either during the course of using Raspbian or when in the process of creating a RaspBerry Pi project, when you will need to transfer files from your Windows PC to your Raspberry Pi device. WinSCP allows you to do that without the need for a USB flash drive. WinSCP (Windows Secure Copy) is a free and open source SFTP, FTP, WebDAV and SCP client for Microsoft Windows. Its main function is secure file transfer between a local and a remote computer. Beyond this, WinSCP offers basic file manager and file synchronisation functionality.

KODI

Kodi is the perfect choice if you want to use the Raspberry Pi as a DLNA media device. Kodi is an award winning free and open source (GPL) software media centre for playing videos, music, pictures, games and more. Kodi runs on Linux and allows users to play and view most videos, music, podcasts and other digital media files from local and network storage media and the Internet. The official Kodi version does not contain any content what so ever. This means that you should provide your own content from a local or remote storage location, DVD, Blu-Ray or any other media carrier that you own.

MOBAXTERM MobaXterm is your ultimate toolbox for remote computing. In a single Windows application, it provides loads of functions that are tailored for programmers, webmasters, IT administrators and pretty much all users who need to handle their remote jobs in a more simple fashion. There are many advantages of having an All-In-One network application for your remote tasks, e.g. when you use SSH to connect to a remote server, a graphical SFTP browser will automatically pop up in order to directly edit your remote files.

FILEZILLA

If you don’t need the full capabilities offered by WinSCP, another option for transferring files is FileZilla. You will see this app recommended during several guides in these pages. FileZilla Client is a fast and reliable cross-platform FTP, FTPS and SFTP client with lots of useful features and an intuitive graphical user interface. FTP has been designed to promote sharing of files across all types of computers. A strength of FTP is the reliable and efficient bulk transfer of files. FTP is popular with website owners and web designers for uploading files to the servers of their web hosting company. www.bdmpublications.com


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Common Raspberry Pi Problems The Raspberry Pi hardware and software is pretty reliable and problems are more often due to set up errors rather than anything to do with the hardware. However, there are times when hardware can seem to be at fault, so here are a few of the more common issues you might encounter when using your Raspberry Pi. TROUBLESHOOTING YOUR RPI

The Raspberry Pi is a surprisingly stable bit of kit, but there is always the chance of encountering problems. If you’re really stuck there are apps available which can help diagnose problems on the RPi.

RED POWER LED IS BLINKING

A blinking red power LED indicates problems with the power supply. On model A and B, it is hard-wired to the 3.3V power supply rail. If it is blinking, it means the 5V power supply is dropping out. Use a different power supply. On the model B+ and also the A+, the circuit has been improved to give a much more reliable warning of poor power quality. The red power LED is wired to an APX803 supervisor which kicks in when the 5V power supply drops below 4.63V. If it does, the LED will blink. Check your connections, cable and power supply.

GREEN LED BLINKS IN A SPECIFIC PATTERN 1 flash:

Possibly you have a Rpi from Micron. Take a good look at the processor if it says M with an orbit round it. Using the latest software will solve your problem; also make sure you have a 4Gb SD card, as a 2Gb doesn’t work. 2 flashes: The SD Card cannot be read. A solution could be to forma the card and flash Raspbian with Pi Installer from Terminal. 3 flashes: Start.elf not found. 4 flashes: Start.elf not launched. 7 flashes: Kernel.img not found. 8 flashes: SDRAM not recognised. You need newer bootcode.bin/start.elf firmware.

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COLOURED SPLASH SCREEN

With the current firmware, a coloured splash screen is displayed after GPU firmware (start.elf) is loaded. This should be replaced by Linux console a second later. However if the coloured screen remains, it suggests the kernel.img file is failing to boot. Try replacing it with a known good one. Immediately after displaying the splash screen, the Pi starts consuming a little more current. If the Pi resets at that moment, it is an indication that the power supply isn’t able to deliver the full current that your Pi requires but dips its output voltage below a minimum when loaded with the full current the Pi needs.

Common Raspberry Pi Problems

NO USB DEVICE WORKS The most common cause of USB devices working is low power supply voltage from a bad PSU, cable or USB hub; but it could also be that no clock signal is present. Return the board for a replacement if you think this is the case but before coming to this conclusion, confirm known good peripherals. A significant number of USB keyboards are not compatible with Raspberry so make sure you are using one made for Pi.

RASPBERRY PI NOT RESPONDING TO KEY PRESSES This is most often caused by inadequate power. Use a good power supply and a good power cable. Some cheap cables that work with a mobile phone, cannot fully power the Pi. Some USB devices require a lot of power; most will have a label showing the voltage and mA requirements. Each one should be 5v 100mA max. Any more than this and they must be used with a powered USB hub. Try unplugging every USB device except the keyboard. You should also note that some keyboards have built in hubs and can try to draw 150mA; Pi can only handle 100mA per USB slot without a hub. Use the latest software too.

Connecting a keyboard and or mouse while a USB Wi-Fi device is connected, may cause one or both devices to malfunction. Tests point to interferences in the 2.4 GHz frequency band in which both Wi-Fi sticks, as well as USB keyboards transmit data. Changing the channel on the wireless access point should fix the problem completely.

KEYBOARD OR MOUSE INTERFERES WITH A USB WI-FI DEVICE

SD CARD PROBLEMS If you have problems, check you have the latest firmware version first. If that is not the problem, try the following. • Some SD cards do not work on the Pi, so check the list of known SD cards on the official Pi website. • If you are having problems setting up your SD card you might want to start by erasing it completely, especially if it has been used elsewhere and still contains data or partitions. • Windows and Mac users can download a formatting tool from the SD Association: https://www.sdcard.org/downloads/formatter_3/ • Reformatting cards is also easy to do in a digital camera. • After writing the image to the SD card, verify that you can see the boot partition when you insert the SD card into your computer. The partition should contain a number of files, including start.elf and kernel.img. If you do not see these files on the SD card, you have made an error writing the image file. • If you are manually preparing your SD card on Linux or macOS using the dd command, this operation will completely erase any existing data and partitions. Make sure you write to the whole card (e.g. /dev/sdd) and not to an existing partition (e.g. /dev/sdd1). • If you put the SD card into your PC in an attempt to write the Pi operating system onto it and the PC tells you the card is writeprotected, even with the write-protect tab in the correct forward position you may have a faulty SD-card rewriter.



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Complete

Raspberry Pi With a Raspberry Pi you can learn to code, build your own web server, create interesting and amazing projects and even build a robot. This book will help you through the entire Raspberry Pi experience, from buying your first RPi to getting it up and running and beyond. We look at how the Raspberry Pi works and guide you through the inner workings of the operating system. We also take a look at the FUZE Project, an amazing learning environment that utilises the versatility of a Raspberry Pi and presents it in a unique and retro-inspired keyboard case. You’ll learn how to start coding, using FUZE BASIC, Scratch and Python and how to use the breadboard for electronics projects. If you’re stuck for project ideas, we will guide you through some examples for you to try out and ultimately improve. If you want to know everything about the Raspberry Pi, then the Complete Raspberry Pi is the book for you. All that’s needed is a little work, and ample imagination. Complete Raspberry Pi can be used with the following Models: Model A

Model B

Model A+

Model B+

Raspberry Pi 2

Raspberry Pi 3

Raspberry Pi Zero

FUZE Project (Raspberry Pi version)

Setup and Basics

Starting off is often the hardest part of any technical project; with that in mind, we help you get up and running in no time. Our step-by-step tutorials will guide you through the process of which models of Raspberry Pi are available, how they work, how you get an operating system onto one and how you can turn it into a useable computer and the base for all your future projects.

The FUZE

We dive into the FUZE Project, one of the most exciting examples of what can be done with a Raspberry Pi, and see what’s on offer. With the FUZE you can use the Raspberry Pi as normal but it incorporates some interesting extras you won’t find on a standard Pi setup. Our detailed guides will walk you through the FUZE and its unique version of the BASIC programming language; we even include some coding examples to sink your teeth into.

Pi Coding

The return of the ‘80s bedroom coder is one of the best examples of how the Raspberry Pi has changed the world of technology. Harking back to a time when limited resources meant more imaginative programming, the Raspberry Pi embraces its technological heritage and provides a stable and easy to learn platform on which to begin coding.

Pi Projects

The Raspberry Pi has been used for some pretty amazing projects by its userbase. Media servers, inside robots, 3D laser controllers, retro arcade machines, the list goes on. It’s even been sent to the edge of the atmosphere in a balloon and, quite remarkably, on board the International Space Station with British Astronaut Tim Peake. The Raspberry Pi, then, really is out of this world technology. Whilst we can’t send you into space (yet) we have some great projects for you to try out.

Complete Raspberry Pi - 2017

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