CanSat Kit User Manual V2014

CanSat Kit User Manual The T-Minus Engineering B.V. CanSat kit V2014 user manual

CanSat Kit User Manual Reference: CSKIT-0001

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Preface This document is part of the T-Minus CanSat kit V2014. The CanSat kit is produced by T-Minus Engineering B.V. for the European Space Agency (ESA).The kit is the product of an extended development period, during which it was subjected to extensive testing by high school students, teachers and specialists. The CanSat kit is a very versatile experimentation set, and provides a basis for an almost unlimited variety of missions. Yet it is still very easy to get acquainted with the working principles, and to prepare the set for its first mission. The complexity of the project is defined by the goals that the CanSat team sets for itself. The developers of this kit sincerely hope that it provides the team insight into scientific missions, that the team will learn and develop skills that are needed during the project and above all: that the team will have a great time and a lot of fun working on the project!


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Preface This document is part of the T-Minus CanSat kit V2014. The CanSat kit is produced by T-Minus Engineering B.V. for the European Space Agency (ESA).The kit is the product of an extended development period, during which it was subjected to extensive testing by high school students, teachers and specialists. The CanSat kit is a very versatile experimentation set, and provides a basis for an almost unlimited variety of missions. Yet it is still very easy to get acquainted with the working principles, and to prepare the set for its first mission. The complexity of the project is defined by the goals that the CanSat team sets for itself. The developers of this kit sincerely hope that it provides the team insight into scientific missions, that the team will learn and develop skills that are needed during the project and above all: that the team will have a great time and a lot of fun working on the project!


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Contents 1

Introduction ............................................................................................................................................................................ 1 1.1

The T-Minus main controller controller board ................................. ................. ................................ ................................ ................................. ................................. ................................. ..................... 3

1.2

The sensor board ........................................................................................................................................................ 4

1.3

The Transmitter and receiver ................................................................................................................................. 6

1.4

Battery ............................................................................................................................................................................ 7

1.5

Mechanical components .......................................................................................................................................... 8

2

Starting with the µC board ................................ ................ ................................. ................................. ................................. ................................. ................................ ................................. .............................. ............. 9 2.1

Connecting and installing the µC board ................................. ................. ................................. ................................ ................................ ................................. ........................... ........... 9

2.2

Writing a first program ................................ ................ ................................. ................................. ................................. ................................ ................................ ................................. ........................... ........... 9

2.3

MCU communication .............................................................................................................................................. 13

3

Electrical design ................................................................................................................................................................. 15 3.1

Design warning ........................................................................................................................................................ 15

3.2

Electrical schematics .............................................................................................................................................. 16

3.3

Components............................................................................................................................................................... 17

3.4

Making the connections ........................................................................................................................................ 31

4

Having hardware and software work together ........................................................................................................ 35 4.1

Sensor readout.......................................................................................................................................................... 35

4.2

Using the transmitter ............................................................................................................................................. 37

5

Building the CanSat .......................................................................................................................................................... 41 5.1

Building the stack .................................................................................................................................................... 41

5.2

The Outer shell ......................................................................................................................................................... 42

5.3

Parachute design ..................................................................................................................................................... 42

5.4

Launch loads ............................................................................................................................................................. 47

Appendix ......................................................................................................................................................................................... 48 A.

Licence information ..................................................................................................................................................... 48

B.

T-Minus µC board ......................................................................................................................................................... 49

C.

T-Minus transceivers ................................................................................................................................................... 51

D.

Driver installation summary ...................................................................................................................................... 52

E.

Installing Arduino ......................................................................................................................................................... 52

F.

Batteries and power system ...................................................................................................................................... 54

G.

Datasheets and USB memory ................................................................................................................................... 58


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1 Introduction The CanSat Kit User Manual was developed in cooperation with ESA’s Education Office to accompany the T-Minus CanSat kit. The CanSat kit forms the basis of the CanSat project. During this project, a scientific mission is designed and all systems needed to accomplish this mission are built such that they fit in a standard soda can. All information necessary to establish a basic CanSat mission with the contents of the kit is provided in this manual. This document comprises the full description of the hardware components included, and a method of assembling the CanSat kit. When this is mastered, the mission can be extended, broadened or even changed completely as desired by the CanSat team. It is advised to quickly read through the entire document before starting actual work: this helps in identifying where to look for information on each step of the building process.

Figure 1 the T-Minus Engineering B.V. CanSat kit


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The CanSat kit contains: 

The T-Minus micro controller (μC) board



The sensor board and its components



The radio transmission system (consisting of 2 identical boards)



A 9V battery and battery connector



The mechanical components of the CanSat



A USB 2.0 cable



USB memory stick with the required documentation

Not included in the kit are the parachute and the outer shell. The reason the parachute is not included is that its design is highly dependent on competition requirements. More information on parachute design can be found in section 5.3 on page 42. The outer shell is not included as soft drink cans are abundantly available. This first chapter provides an introduction of the components in the CanSat kit to allow the understanding of their functions. The other chapters are a guide to understand the steps required for building a CanSat. Chapter 2 of this document describes the software side of the µC board and how it can be used. In Chapter 3, information on designing electrical circuits (hardware) is provided and the electrical components of the kit are discussed. Chapter 4 describes the interface between hardware and software. Chapter 5 helps in putting the CanSat together by discussing the mechanical components, including guidelines on how to make a parachute.


1.1

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The T-Minus main controller board

The T-minus main controller board (µC) is the brain of the CanSat. The board houses the ATmega2560 micro controller and the hardware required to operate the micro controller. The extra hardware is comprised of a power supply and a USB communication/programming interface.

Figure 2: The T-Minus micro controller board

The power supply provides two input options for powering the device either using a USB connection or an external power supply (battery). The CanSat can be powered via the USB connection during the testing and programming and by a battery during full system tests and the actual launch. The main software development environment used to programme the CanSat is Arduino. Arduino offers a simple method for programming the device, although it limits some of the functions of the microcontroller. Any type of battery can be used to connect to the power input, as long as the battery voltage is between 5.5 and 15V. The board can be set to run on 5V (default) or 3.3V. The operating voltage can be chosen depending on the components that are connected to the board. The board can deliver up to 800mA when using a battery and up to 500mA when connected via USB. Information on all the connections of the µC board is located in appendix B: T-Minus µC board.


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Arduino

Arduino is an open source electronics prototyping platform based on flexible, easy-to-use hardware and software. Most of the information regarding programming using this environment can be found on the Arduino website ( www.arduino.cc ) and on dedicated forums. See appendix A for license information.

1.2

The sensor board

The primary mission of a CanSat is to measure pressure and temperature to determine altitude. To be able to do this, it uses sensors. To connect these to the µC board, a dedicated sensor board was designed to provide flexibility to the user. The solderable holes are each at 2.54 mm apart - the most widely used standard distance between the feet of electrical components. More PCB material is readily available: search for europrint or eurocard in electronic shops. The sensor board is placed on the µC board with 3 connectors of 20 pins. These connectors have 16 data lines and 2 positive and 2 negative power supply lines.

Figure 3: An empty CanSat kit sensor board


1.2.1

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Measuring the Temperature

For the temperature measurement the kit provides two sensors, one is a thermistor and the other is an integrated circuit. The two sensors use different methods to read the temperature. Sensor 1: The thermistor

A thermistor is a resistor where the resistance depends on the temperature of the component. The CanSat kit uses a negative temperature coefficient, or NTC thermistor (the resistance of the thermistor decreases when the temperature rises) manufactured by VISHAY BC Components, model NTCLE203E3103GB0. The datasheet, attached in appendix G and in the datasheets folder on the USB memory stick, shows the value of the resistor at several temperatures.

Figure 4: The thermistor (source: nl.farnell.com)

Sensor 2: the integrated circuit

The second temperature sensor is an integrated circuit manufactured by Texas Instruments, model LM35. The datasheet of the LM35 sensor is attached in appendix G and can be found in the datasheet folder on the USB memory stick. This sensor is simpler to use, but give less insight in how the measurements are performed. Care has to be taken when connecting active components like the LM35. As this is an active component, and reversing the power supply will damage the device or even destroy it. The NTC in contrast is a passive component and does not br eak when connected in reverse.

Figure 5: The LM35 temperature sensor (source nl.farnell.com) 1.2.2

Pressure sensor

For the pressure measurement, the kit contains a MPX4115 sensor, produced by Freescale™


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the LM35: take care when connecting this device. More information on the sensor can be found in the datasheet that is added in appendix G or can be found in the datasheet folder on the USB memory stick.

Figure 6: The MPX4115A pressure sensor (source nl.farnell.com)

1.3

The Transmitter and receiver

The transmitter and receiver are two identical boards called transceivers. The T-Minus transceiver delivered with the CanSat kit has two methods for connecting the board. One method uses the 3 20-pins headers on the board to connect with the µC b oard. The other method uses the USB connector to connect with a computer. This allows the board to be used in a flexible way without the need for extra components.

Figure 7 T-Minus transceiver board

The transceivers are provided with a wire antenna soldered on to the antenna connection. This allows immediate use of the two transceivers. An SMA connector is provided to allow the connection of external antennas like high-gain Yagi antennas. Information on this subject can be found in chapter 3.3 on page


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The transceiver operates around the 434 MHz frequency with an output power of up to 13 dBm. Using frequency shift keying as modulation method allows the transceivers to operate in sounding rocket applications. Frequency, transmit power and data rates can be changed using the Graphical User Interface (GUI) provided on the USB memory stick. The default settings of all the boards are identical, allowing the immediate use of the transceivers. During the CanSat competition, different operating frequencies will be appointed to different teams to prevent interference.

1.4

Battery

The 9V battery provided with the CanSat kit can be used to start working with the CanSat from the moment the box is opened. With the 9V battery clip of the kit, these batteries can be connected easily. It is advised to always connect a new battery before launching the CanSat. It would be unfortunate and unnecessary if there is no data from the CanSat because of an empty battery.

Figure 8 Battery and battery connector


1.5

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Mechanical components

The CanSat kit contains several components to make the structure of the CanSat and fit it inside a soda can. The round end plates can be used as top and bottom for the CanSat using the M3 treaded rods and nuts for fitting the electronics. The M 5 eyebolt can be used to connect the parachute.

Figure 9 mechanical components of the CanSat kit

The USB cable, a standard USB 2.0 cable from USB A plug to USB micro B plug, can be used to connect the µC board or one of the transceivers to a computer. These cables are widely available, as most modern mobile phones use the same cable. The USB memory stick contains all the required information to use the CanSat kit.


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2 Starting with the µC board The µC board is the brain of the CanSat. In space systems engineering, this is mostly referred to as master control unit or MCU. The T-Minus µC board has 3 20-pins headers that can be used to connect other components. These headers provide 46 general inputs and outputs and 2 analogue outputs. For details on the functions of each pin see appendix B: T-Minus µC board. This chapter explains the necessary steps to program the µC board and provide a guide for writing a first program. The first program has similar functionality as the famous "hello world" used by website designers. The main reason for such a program is that it provides a quick and basic check if all the interfaces are working.

2.1

Connecting and installing the µC board

The µC board is connected to the computer with a USB cable. This connection can be used to program the micro controller. It also provides the option to communicate between the computer and the µC board. This communication can be used to test the program code that is made. The program that is present on the micro controller upon delivery of the CanSat kit blinks all the 8 LED's when powering the board via USB or the external power supply. When connecting the board to a computer for the first time a driver need to be installed. This driver can be found on the USB memory stick, under: "programs/ (your operating system)". The driver will require administrator rights on the computer to allow installation. Read through appendix D: Driver installation for more information on driver installation. After successful installation, the driver will create a serial com port. The number of this port will be between 1 and 10 for most computers, but can have any number up to 256. The transceiver board uses the same driver as the µC board, dese drivers only need to be installed once. License information on the drivers and board firmware can be found in appendix A: Under Licence information.

2.2

Writing a first program

The software development environment used to write the software for the micro controller is Arduino, as mentioned before. A version of Arduino can be found on the USB memory stick, but the newest version can also be found on the Arduino website, www.arduino.cc. Installing Arduino is done by unpacking the zip file located in the folder indicating your operating system, or using the .exe file for windows.


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T-Minus variant

To use the T-Minus µC board in Arduino, it has to be installed first. To install the T-Minus variant and several examples for using the T-Minus boards, several steps have to be completed. The USB memory stick has all required files in a zip file, located in "programs/T-Minus files for Arduino.zip". This installation is independent of the operating system used. Follow these installation steps carefully: 



Finding the sketchbook location. o

Run Arduino

o

Go to file->preferences

o

Get the Sketchbook location

Close Arduino o

IMPORTANT, since this is the first time Arduino is closed, the Sketchbook location folder is created at this moment



Open a file explorer o

Go to the Sketchbook location

o

Extract "T-Minus files for Arduino.zip" to the Sketchbook location



Run Arduino



Go to "Tools->boards" and select "Tminus1" as board



Go to "Tools->Serial port" and select the serial port used by the T-Minus board o

The bottom right of the screen will now indicate "Tminus1 on comX" where X is the selected com port.

For a more elaborate explanation on installing the T-Minus variant see appendix E: Installing Arduino.

2.2.2

Initial program

In order to determine if the device works and verify that you can program it, you have to run a small program. To do this, the program shown in Figure 10 can be written to the μC board. It uses C as programming language. This Arduino program is on the micro c ontroller when it is delivered.


Figure 10: The Arduino program on the board when it is delivered.

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2.2.3

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Step by step explanation of the program

The top of the screen indicates BlinkAll_TMinus | Arduino 1.0.2. These are the file name given to the initial program and the version of Arduino, in this case Arduino version 1.0.2.

The bottom right of the screen shows “TMinus1 on COM4” This indicates that in this case the TMinus1 board is used and that it is connected to COM4. The number of the com port used will be different on every computer. The program is comprised of two parts: the "setup' and the "loop" part. The setup part of the program is run only once. This part is used to setup the controller and define initial values for variables. In the case of the original program, this is used to set the micro controller outputs of the LED allowing turning the LEDs on and off.

The lines “pinMode(xx, OUTPUT);” is the call to function pinMode which is pre -defined in Arduino. The pinMode function is used to determine if a pin of the microcontroller is used as input or output. The number is a reference to the digital pin number defined in the Arduino variant being used. In appendix B: T-Minus µC board, a list of the functionality of each micro controller pin is given. Pins 16 to 23 are connected to the LEDs. The last part reads OUTPUT. This tells the micro controller to control this pin as output, allowing the user to set them at either "high" or "low" state. The low state is set by default. The loop part is run continuously by the micro controller from top to bottom. There are two functions

used in this loop. The first is “digitalWrite(xx, HIGH/LOW);” used to set the voltage for the pin at 5V (high) or 0V (low). The LEDs will turn on when the pin is set as digital output low . The reason for this is a choice

in board design. The second function is “delay(xxxx);” this makes the micro controller wait for a number of milliseconds, depending on the value that i s given as the parameter between brackets.

2.2.4

Verify and programming your initial program

The Arduino software has the ability to verify if the program you wrote is in compliance with the programming rules. This verification checks if the syntax, or programming language, has been followed. The verification does not check if the program will do what you want. For this reason, programming should be done in small steps. Verification is done by pressing the "verify" button in Arduino (indicated by the checkmark). When there are no problems, the program can be uploaded to the micro controller. To start this process, press the Upload button, indicated by the right pointing arrow. The status bar in the bottom of the screen will show "Verifying", followed by "Uploading".


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The T-Minus µC board has a jumper, as shown in appendix B: T-Minus µC board. This jumper enables the easy programming using Arduino. This also means that the micro controller is reset when USB communication between the controller and computer is initialized. If this reset is unwanted, the jumper can be removed. In this case, programming via Arduino is not possible.

2.3

MCU communication

Communication is one of the most important parts of the software. While the LED’s provide basic feedback that the device is working and that your program is uploaded correctly, they cannot be used as for reading out the sensors. A serial communication link will be used to send extra information to the computer and in a later stage also to send data to the transmitter. There are many forms of communication that can be used by the micro controller on the T-minus board. There are 2 main groups of serial communication used in microcontrollers: synchronous and asynchronous. In synchronous communication, a clock line will tell the receiver when to read the data from the data line. In asynchronous communication, there is no clock line available, so the timing between the data bits is important to allow for correct readout. The basic communication method of Arduino is a UART connection to the computer. The UART, or Universal Asynchronous Receiver/Transmitter, is a serial communication system with separate transmit and receive lines. On the computer, this is connected to the com port. During installation of the drivers, a virtual com port is created for this purpose. As UART is an asynchronous communication protocol, the timing of the line needs to be (almost) identical for the transmitter and receiver. This timing is called baud rate, or the amount of digital bits transmitted per second.

2.3.1

Setting up the UART communication

To setup the micro controller for sending communication to the computer the following function is used in the setup part of the program: Serial.begin(9600);

Serial.begin is the function setting up the communication and 9600 is the baud rate at which the communication will run.


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The next step in sending information is telling the program what to send. This can be done in the loop part of the program or in the setup part (while not above the "Serial.begin" function). There are two different functions for this: Serial.print(); Serial.println();

The difference between the two is that the “ln” stands for "line", indicating that the program will send the commands for new line at the end after the printing. The data transmitted is between the brackets. The text to be sent is placed between “ ” , such as “text to be send”. To send the value of a variable, place the name of the variable between the brackets, like (variable).

Serial.print(“text to be send”); Serial.print(variable);

The last part is having the computer monitor the communication via the com port. Arduino has a socalled serial monitor built in. The same com-port that was used for programming is monitored here. To open the serial monitor, click on the serial monitor button.

At the bottom right of the screen, a drop down menu allows the selection of the baud rate. Setting this to the same value as used in de program will show the data that is sent. Try sending text and variables with and without new lines to get a feeling for operation of the UART communication.

2.3.2

Other UART options and the transmitter

The T-Minus µC board has not only one, but 4 UART connections. One of these is connected to the USB port that was used previously. To use the other UART ports, simply replace the "Serial" part in the program to "Serial1", "Serial2" or "Serial3", representing UART ports 1, 2 and 3: Serial1.begin(9600); Serial1.print(“text to be send”);

When the transmitter is connected to the bottom of the µC board it is automatically connected to UART port 1, or "Serial1". The pins that are used for Serial1, 2 and 3 can be found in Appendix B: pin functions


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3 Electrical design Now that the MCU is working, it is time to think about connecting other components like sensors and transmitters. All components needed for the system used for the primary CanSat mission are provided, but they need to be built together. Next to that, there are many options for secondary missions, of which most require additional electrical circuits. This chapter provides a short description of electrical circuits and the basics of designing and building them. An electrical circuit is a network of electrical components, designed to fulfil a specific task. There are many different types of electrical circuits, like your computer or a telephone. More simple circuits are for example the light above the dinner table, or a flash light. The flash light circuit contains three components: a battery, a switch and a light bulb.

Switch

Battery

Lamp

Figure 11: schematic diagram of a flash light

Figure 11 shows a schematic representation of the flash light circuit. In a schematic circuit diagram, the components are represented by symbols. Many different components have a dedicated symbol but there are also components that do not. The meaning of the symbols depends on the system us ed. There are two widely used systems: the American and the European. The reason symbols are used in circuit diagrams is to make it more readable. Search on the inter net for “Electrical circuit symbols” to find more. The components are connected to each other by electrical wires. I n an electrical circuit, the wires are normally not called components but connections. In the above picture they are represented by the line s connecting the components. These lines indicate an electrical connection with very low resistance. In most systems, copper wire is used for the connection but other options are possible as well.

3.1

Design warning

When starting with a design, it is wise to work in small steps. While the manual describes al similar


3.2

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Electrical schematics

In properly drawn schematics, there are three rules applied to make the circuit readable. The first is reading from left to right. This means inputs are placed on the left side of the circuit and outputs on the right. In the flash light circuit, the battery is the input and the light bulb is the output. The second rule is to work from top to bottom. For electrical schematics this means high voltages are on the top of the diagram and low voltages are on the bottom. The positive supply of the battery is drawn at the top and indicated by the longer line and the plus sign. The last rule is the way the connections are drawn.

Label

Label

Label

Label Not connected junction

Connected junction

Use of labels

Use of labels

Figure 12: schematic diagram of connected and not connected wires. Th e labelled wires are connected

In the simple schematic of the flash light there are only 3 connections in only one loop. The simplicity of this circuit makes it very clear. In more complicated circuits there are many more connections. Figure 12 shows how to draw connected and unconnected crossings. The two lines are connected when they are drawn with an offset, and not connected when they cross. The power lines in an electrical circuit are normally connected to many components. To prevent the situation where the drawing contains too many lines, which would make the diagram difficult to read, labels are used. As shown in the Figure 13, all connections with 3V are connected together. The same holds for the 0V connections. However, for the flash light circuit, using only labels does not make the schematic more readable. Finding a balance between labels and lines is dependent on many aspects and on the choice of the designer.

3V

3V

Battery

Line2

Switch

0V

Line2

Lamp

0V


3.3

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Components

Many different electronic components are available. The core of every CanSat is built up with a few basic components. These components are: 

A micro controller



A power supply



some sensors



A transmitter

In this manual, the T-Minus CanSat kit is used as reference. The same principles apply to other components.

3.3.1

Micro controller

The micro controller is the main controlling and calculating component of the CanSat. There are many manufacturers of micro controllers, which all make almost infinitely many different versions. All of these controllers are based on a sequential processor, surrounded by several hardware interfaces. These interfaces include systems like memory, analogue-to-digital converters and digital communication systems.

Figure 14 Schematic view of the ATmega88PA micro controller. The schematic is divided into an input/output part (U5A) and a power supply part (U5B). The ATmega88PA is pictured as the ATmega2560 h as much more pins the principle is identical.

As the micro controller is a part that has many connections (sometimes up to 144 pins!), a discussion of all connections is not part of this document. Detailed information can be found in the datasheet of the


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The first type of connection is the “general input/output” or GIO. In the Atmel micro controller , all input/output pins can be used in this manner. Connections starting with PB, PC, or PD are GIO pins. A GIO pin can be used as input, where it will read a logical 0 or 1, depending on the voltage that is applied to it. The GIO can also be set as output, so that the software determines if the pin is held high or low. If the pin is held high, it will supply the same voltage as is being supplied at the VCC pin(s). When the GIO pin is held low it will drain current such that the voltage is kept at 0V. The second type of connection is the analogue-to-digital converter (ADC). Many micro controllers have

ADC’s on-board. These can be used to measure a voltage between 0V and the supply voltage. The precision of the measurement depends on the amount of bits the ADC provides. Most ADC’s in microcontrollers are 10 bit. A 10 bit ADC divides the voltage range in 2^10 = 1024 different steps, where 0 is the minimum value and 1023 is the maximum value. The ADC inputs of the micro controller can be recognised by the labels ADC0 to ADC5, for the micro controller of Figure 14

Figure 15 Basic principle of an ADC (source: wiki.ulcape.org)

The T-Minus µC board contains 2 Digital to analogue converters (DAC). These converters work in the same as the ADC's it but then in reverse. The two DAC's on the b oard are the MCP4725A0T-E/CH and are controlled via I2C communication. More information on I2C can be found on the Arduino website. Information on the MCP4725A0T-E/CH can be found online, search for MCP4725A0T-E/CH and datasheet. The 7 bits address of the DAC is "1100000" for analogue output 0 and "1100001" for analogue output 1.


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The last connection of the micro controller that will be discussed in this document is the UART connection that was discussed in section 2.3.

Figure 16 basics of UART communication

For a UART connection, the output of one device is connected to the input of a different device. In Figure 16 the basic protocol is shown. The connection is held high by the transmitter before the communication starts. The transmitter starts the communication by making the line low for a predetermined time. This is done to tell the receiver that data will be transmitted. After this start bit, one or several data bits are transmitted. At the end of the transmission, a s top bit is sent to make the line high again. Normally, 8 bits or 1 byte are transmitted between a start and stop signal. UART connections consist of a transmitter and a receiver. For two way communication 2 separate lines are required, where the transmitter of one system is connected to the receiver of the other. The schematic representation of the µC board is different than the representation of just a micro controller. The connections of the schematic should only show the connections that can be made to the board. A typical schematic will be presented after the power supply is described, as the microcontroller board also provides the power supply.

3.3.2

Power supply

The power supply in the CanSat kit is a combination of the battery and the voltage converter located on the µC board. For information on battery selection see appendix F: Batteries and power system. The


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provides power for the external components on 12 pins: 6 times a 5V or 3.3V and 6 times the 0V (ground) reference.

Figure 17 µC board Schematic

As seen in the above figure, the schematic of the µC board can be divided into 4 parts. Three times a 20pin header and the battery connector. The USB connector is not placed in this schematic as it is not used as part of the CanSat. Note that the method to draw this schematic is not unique. This is only one way to present it, given as an example. Linking the board schematic to the hardware of the board is very important to prevent any mistakes in building the electronics. The most common reference between schematic and physical components is the use of pin numbers. This is especially useful in components with many pins as it makes counting to the correct pin easy. In the above schematic of the µC port, there are 3 20-pin connecters which all start counting at pin 1. The name of the header points to the correct header and pin 1 is indicated on the board by the "1" (on the sensor board, a square solder pad is used to indicate pin number 1). The schematic in Figure 17 does not show the LED's as they cannot be connected in any other way. The LEDs are connected to digital pins 16 to 23. Logic high ("1") turns the LED's off and logic low ("0") turns them on. The reason for this is for power purposes, most micro controllers can sink (pulling a line low) more power than they can provide (pushing a line high).

3.3.3

Sensors

Sensors can be used to measure many different things in many different ways. All sensors can be divided into two groups: digital sensors and analogue sensors. Analogue sensors alter an electrical quantity, like voltage, current or resistance, which can then be measured. Digital sensors have this measurement


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microcontroller. In this document, only analogue sensors are described, as it is easier to understand the basic principles with this type of sensors. All sensors provide their output within certain limits and under certain conditions. All sensors need at least two connections to work. The first is the output connection and the second is the power connection. For the power connection, this includes both the positive and negative connections. The datasheet of the component provides information on how to connect and use the sensor.

3.3.4

Pressure sensor

Starting with the MPX4115 pressure sensor the important parts of the datasheet will be discussed after which the procedure for making the connections is described. The complete datasheet can be found in appendix G. G. The first important part of a datasheet is the list of operational characteristics. These characteristics describe properties like sensitivity, accuracy, maximum and minimum operating voltages and current consumption. Table 1 characteristics sheet of the MPX4115 Datasheet Characteristic Pressure Range(1) Supply Voltage(2) Supply Current Minimum Pressure Offset(3) (0 to 85°C) @ VS = 5.1 Volts Full Scale Output(4) (0 to 85°C) @ VS = 5.1 Volts Full Scale Span(5) (0 to 85°C) @ VS = 5.1 Volts Accuracy(6) (0 to 85°C) Sensitivity Response Time(7) Output Source Current at Full Scale Output Warm-Up Time(8) Offset Stability(9)

Symbol Pop Vs Io Voff

Min 15 4.85 0.135

Typ 5.1 7 0.204

Max 115 5.35 10 0.273

Unit kPa Vdc mAdc Vdc

Vfso

4.725

4.794

4.863

Vdc

Vfss

-

4.59

-

Vdc

V/P tR Io+ -

-

46 1.0 0.1 20 ± 0.5

± 1.5 -

%Vfss mV/kPa ms mAdc mSec %Vfss

Starting at the top of the Table the Table 1, the 1, the pressure range is the range of pressures the device can measure. The supply voltage indicates the voltage required on the Vs pin in reference to the GND pin to use the sensor. The board provided with the CanSat kit has a 5V power supply, which is within the range indicated in the table. The supply current of this device is normally 7 mA with a maximum of 10 mA. This current can be used in calculations on required power supply or the expected battery life. The next lines describe how the Vout pin reacts to the applied pressure. This part will be required during calibration and analysis of the signal. For this part it is important to note that the output is an analogue voltage, with a


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Now that the information on what the component does is gathered, it is important to find out how to make the required connections.

Figure 18: part of the datasheet from the MPX4115 pressure sensor (source Motorola)

The MPX4115A pressure sensor has 6 electrical contacts. The datasheet of the sensor describes the function of each pin. As seen in Figure in Figure 18, pin 18, pin 1 is Vout, pin 2 is GND, pin 3 is Vs the other pins are N/C or

“not connect” pins. For this component , there is no predefined symbol is available, which means we have to make one ourselves. Since there are only 3 connections used, the symbol will only contain 3 pins. Vout, or output voltage, is an output, so it is placed on the right side of the symbol. GND is ground , or negative power supply and is therefore placed at the bottom of the symbol. Vs, or supply voltage, is the positive power supply and will be placed at the top.

Figure 19: self-made symbol for the MPX4115

Combining the schematics of the pressure sensor with the µC board results in the connection scheme


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the options that can be used to connect the pressure sensor. In this schematic pin number 1 and 2 of the analog connector are used to power the pressure sensor. This connection can be made to any of the power pins on any connector. Using a power supply located close to the component when placed results in better performance.

Figure 20 connected pressure sensor 3.3.5

Temperature sensor

The CanSat kit contains two temperature sensors based around two different measurement setups. The first to be discussed is a thermistor, the second is the LM35. A thermistor is a temperature dependent resistor. To measure the temperature with a thermistor two basic setups are possible: on can either put a voltage across the thermistor and measure the current, or send a current trough the thermistor and measure the voltage. This principle follows from Ohm's law: U=IxR, where U is the voltage over the resistor, I is the current through it and R is its resistance.

A R(T) thermistor

Voltage Source

+ -

R(T)

Current Source

R(T)

V

Figure 21: thermistor symbol and the measurement options.

The methods shown in Figure 21 either need a current source or current measurement. The simplest current measurement is the use of a resistor with a fixed and predefined resistance, to convert current in


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5V R(T) A1

Analogue input of the micro controller

R 10kΩ 0V

Figure 22: readout of the thermistor

Together with the resistor, the thermistor can be connected like the pressure sensor, in order to read the output voltage.

  () 

   ()  

          

The above formula describes the relation between measured voltage and the resistance of the thermistor. With this resistance the, temperature can be calculated from the thermistor datasheet. The NTCLE203E3103GB0 thermistor made by VISHAY BC Components is part of the CanSat kit. The complete datasheet can be found in appendix G. appendix G. This This is a negative temperature coefficient thermistor, thermistor, which means that the resistance decreases with increasing temperature. Table 2: part of the table describing the relation between temperature and resistance from the thermistors datasheet

Temperature

resistance

°C

kΩ

0

32.56

5

25.34

10

19.87

15

15.70

20

12.49

25

10.00

30

8.059

35

6.535

40

5.330

The datasheet of the thermistor shows a table of the relation between temperature and resistance, of


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The LM35 temperature sensor works different then the thermistor as it is an active component. The datasheet of the LM35 can be found in appendix G. The LM35 has 3 pins: an analogue output, a positive power pin and a negative power pin. The schematic is very similar to the MPX4115.

Figure 23 schematic and physical representation of the LM35 3.3.6

Transceivers

The T-Minus transceiver boards, or RF boards in short, can be treated as one component. Although the board has 3 times 20 pins headers, only 4 pins are required to be connected to the µC board the other pins of the RF board are not connected. Placing the RF board beneath the µC board will automatically create the correct connections. By means of the USB connection cable, the RF board can be connected to the computer no other connections are required in this method.

Figure 24 Transceiver connected with the µC board

When the transmitter board is connected directly to the µC board all required connections are made in the correct manner. Nevertheless it is i mportant to understand what connections need to be made for the transceiver to work.


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Figure 25 the transceiver board and its schematic representation

Figure 25 shows the board and the schematic of the transceiver. A note of importance is that the connections indicated in the schematic are all located on the 20 pins Bus connector. The TX and RX are connected the other way around then they were at the µC board: the transmit (TX) pin of the RF board connected to the receive (RX) oin of the µC board and vice versa. This is required for the UART communication to work properly. Radio communication is the sending of information from one place to another- using electromagnetic waves, also called radio waves. Electromagnetic waves are generated at an antenna when an alternating electric current is connected to it. The antenna transforms the electric current into electromagnetic waves. At the receiving end of the communication the waves are transformed again in-to electric current by a receive antenna. Using the radio waves to transfer information means this information needs to be added to the radio frequency used. Adding this information is called modulation. This can be realised in several ways. The most basic form is to transmit a (carrier) frequency or not. This is so-called continuous wave (CW) communication. The most used form of CW is Morse code. The most important drawback of this form of modulation is that the information transfer rate or baud rate is very low. There are many other forms of modulation, like AM and FM. These are used by radio stations. With AM the information is included by changing the amplitude of the carrier frequency. In FM the frequency of the carrier is changed,. As depicted in Figure 26. The advantage of FM over AM is that the signal strength does not interfere with reception.


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Figure 26 the difference between AM and FM modulation (source: www.scriptasylum.com)

The CanSat kit has a transmitter working with Frequency Shift Keying (FSK). This means it is transmitting at a certain frequency when a logic 0 is transmitted and at different frequency if a logic 1 is transmitted, as depicted in Figure 27. There are many other forms of modulation like QPSK where two bits are transmitted simultaneously.

Figure 27: frequency shift keying FSK (source: en.wikipedia.org)


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other aspects can be influenced, but a different transmitter and receiver are required for this, which is beyond the scope of this document. Two antennas are used for receiving the information from the CanSat. The first is the antenna on board the CanSat the second is the antenna used at the ground station. The antennas need to be made with different requirements although the frequency of operation is similar to both antennas. The antenna on board the CanSat needs to be isotropic (as much as possible). This means that it transmits the same amount of power in all directions, allowing the reception of the CanSat independent of its orientation. The antenna connected to the ground station can be made high-gain, directional antenna. This means that it receives more electromagnetic waves from one direction then from another. This antenna needs to be pointed at the CanSat during the mission, ensuring that maximum power is received.

Figure 28: an “Arrow” which is a Yagi antenna for operation at 2 different frequencies (source: purplesage.biz)

Figure 28 shows a directional Yagi antenna that operates at two different frequencies. The antenna has a 7 elements Yagi for 433 MHz and a 3 elements Yagi for 145 MHz. For receiving the CanSat, using a Yagi antenna might be a very good option, since it can be constructed relative easily, using wood and copper tubes. More than enough information on how to build a Yagi antenna is available on the internet. Google for "Yagi antenna" or go to "http://makeprojects.com/Project/Homemade+Yagi+Antenna/623/1". To connect the ground station antenna the SMA connector provided in the kit can be used. To install the connector, the wire antenna needs to be removed. Three options are available for placing the SMA connector, as shown in the following figures.


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Figure 29 Options for placing the SMA connector

Warning when placing the SMA connector on the top of the board: "this will prevent the board from being placed underneath the µC board". If the SMA connector is not an option for the ground station, then the

wire can be soldered directly onto the PCB. Make sure to connect both cables of a coaxial cable, the inner cable to the inner part of the board and the outer cable to the outside. Use a multimeter to measure if the wires are not shorted. The CanSat antenna needs to be robust to survive the launch on a rocket. A so-called quarter wave wire antenna works very well for this. The term "quarter wave" describes the length of the antenna in reference to the operation frequency. The transmitter of the CanSat kit operates at around 434 MHz. the precise frequency depends a bit on what team you are in. This is done to protect each other from interference.

(    )       (        ) The formula shows that the length of the antenna should be around 17.3cm. The wire can be soldered to the antenna contact of the transmitter board directly, or when using a coaxial cable, the antenna can be placed some distance away from the board. When using a coaxial cable, the last 17.3cm of the outer conductor needs to be removed to form the actual antenna. Be sure to protect the insulation material since electric contact with metal surfaces might damage the transmitter.

3.3.7

Complete sensor schematic

With all the sensors described, a complete schematic can be drawn with all the sensors and components. However, before this is done, one more subject needs to be discussed: sensor noise. Analogue sensors are more perceptible to noise then digital ones. The main reason for this comes from the basic operation principle of the sensor. Analogue sensors change their output relative to the measured quantity. A small change in measured quantity only results in a small change in output voltage. However, other external factors, such as electromagnetic interference or fluctuations in the power supply, may also vary the


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this effect, since the signal is not dependent on small changes in output voltage. Noise therefore has less of an effect. Two simple methods exist to reduce the noise. The first is the use of capacitors in the connection on between the sensor and its power supply. These capacitors decrease the fluctuations in the power supply and therefore decrease the noise the sensor produces. Capacitors could also be used at the output of the sensor but care must be taken that the sensor can handle the extra output capacitance. In the total schematic of Figure 30 capacitors are added between the power connections of all the sensors. The second method to reduce noise will be discussed in paragraph 3.4.

Figure 30 Complete schematic of the CanSat kit


3.4

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Making the connections

The schematic in Figure 30 shows which pins should be connected together. When building the circuit, it is very important to create exactly what is represented in the schematic. The circuits are built by placing the components on the board and then using wires to connect them. These wires need to be placed such that the schematic diagram and built circuit are the same. Using short wires is better than long wires. The longer a wire, the more resistance it has and the more noise it will pick up. Long wires will influence the circuit and result in unwanted behaviour.

Figure 31: an empty CanSat kit sensor board (courtesy of T-Minus)

The PCB (printed circuit board) provided with the kit for the building of the primary mission is a semispecific PCB. The PCB is designed in the shape of the main board with the solderable holes aligned such that they can connect to the connectors of the main PCB. All the connections that go to the main board have an extra hole connected to them to make connecting wires easier. Looking closely at the board, the lines that make these connections can be seen. Placing the components is a puzzle where the complexity is dependent on the amount of components and your personal demands on circuit size. Placing the components close together makes the design harder, but less board space is used. Leaving room for the wires will ease the soldering later while the board space required is increased. Building a PCB is planning ahead. Designing a specialized PCB is a method to make soldering much simpler and creates less of a hassle


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components are much smaller than that. A large variety of programs is available for designing PCB’s. One that has a free licence for non- commercial use is the computer programme “Eagle”. After the PCB is designed in such a program it needs to be fabricated. Many companies exist that are specialized in PCB manufacturing.

3.4.1

Soldering

Soldering is needed to connect the components electrically and mechanically. To solder the components, they need to be heated and then solder needs to be added. The required soldering temperature is depending on the type of solder used. Solder made for electrical circuits melts at around 183 degrees Celsius for leaded versions or around 230 degrees Celsius for lead free solders. For making a good solder joint, it is important that both surfaces are heated to a higher temperature than the melting point of the solder. If one of the surfaces is not hot enough, the solder will not make a good connection, resulting in a non-functioning electric circuit.

Figure 32: the anatomy of a good solder joint

The tip of the soldering iron is around 350 degrees. This is hot enough to destroy almost all components. Luckily it takes quite some time to heat up the actual component to this level during soldering. The time needed to make a good solder joint is much less, although some time is required to heat up the solderable surfaces sufficiently. Generally speaking it takes between 1 and 2 seconds to make a good solder joint. Below are several pictures of good and bad solder joints


Figure 33: drawing of good and bad solder joint

Figure 34: photographs of bad soldering (courtesy of T-Minus)

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When placing the components, it is good practice to start with the headers as this is an easy way to get the feeling of soldering. The black parts of the headers need to be placed at the top side of the board (the side with the white lines, as in Figure 36). If the headers are placed on the wrong side the positive and negative voltage are reversed,

Figure 36 CanSat sensor shield with headers.

Before placing the other components, make a plan where to place the components and how to connect them. Placing all the components in the board before making a solder connection makes planning easier. From here there are several options. A good advice is to go step by step and test every connection if possible before continuing with the next. As example the MPX4115 can be soldered and tested before the other components are placed.


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4 Having hardware and software work together In most modern electrical systems the hardware and software needs to work together. The CanSat has two important parts that can be identified, readout of the sensors and using the transmitter.

4.1

Sensor readout

To use the sensors, several steps need to be taken. The readout of the sensor is done by measuring the voltage provided by the sensor. This voltage measured is converted in to a digital value that represents this voltage. The difficulty is mainly the calculation back from the measured digital value to the actual measured quantity. In case of the pressure sensor, the binary value (an integer value between 0 and 1023) needs to be converted back in to the pressure.

4.1.1

Analogue read

The function used to get the binary value is "analogRead( )". This function requires two things to work: a variable in which to place the binary value, and an indication of which analogue port to read. The variable needs to be defined before it can be used. This is done in the following line: int Analog0; // this is a variable definition of a variable called Analoge0

Next, the port of which the value should be read has to be put in the function as a parameter: Analog0 = analogRead(A0); // the analogue voltage of port A0 is stored in Analog0 in binary form

The port needs to represent one of the analogue ports of the microcontroller. The T-Minus µC board has 12 analogue ports ranging from A0 to A11. The value now placed in Analog0 is a value between 0 and 1023. Were 0 represents a measured value of 0 volts and 1023 represents a measured value of 5V (or 3.3V if the µC board works on 3.3V). Any value between 0 and 1023 represents a value between 0 and 5V. The micro controller can be used to convert this binary value in-to the voltage, and even in-to the corresponding pressure. However, this can be done on a computer of the ground station during the mission, or even after the mission. It is up to the CanSat teams to determine which part of the calculation is to be performed by which part of the system. One reason for choosing on board computing is discussed later in this chapter.


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Making calculations in the program can be done the same way as the analogread() function. While calculations can be done with integers (the variable Analog0 is an integer) most measured voltages cannot be represented as integer. To make the calculation easier to read the value can be converted in to a floating point variable, which can represent values with decimal points. float Analog0float; // the float version of analog0 float Analog0withcalc; // a float to place the calculation done to analoge0 Analog0float = (float)Analog0; // converting Analog0 to floating point variable Analog0withcalc = Analog0float * 2 / 1012; // calculating with variables

In this example a new variable is created for every new step. The creation of all these variables is actually not required as the answer of a calculation can also be placed in the variable used as input. This reuse of variables makes more efficient use of the micro controller's memory. However, this is only true if the answer and input variable are of the same type; integers cannot be placed in floating point variables. Sending the values to the computer to be able to read them can be done by using the Serial.print() and Serial.println() functions. Serial.println(Analog0); Serial.println(Analog0float); Serial.print(Analog0withcalc);

These lines send the values of the variables. Good practice is to start with trying what the different print functions will provide.

4.1.2

Calibration

An important step in measuring with sensors is to determine the formula used to convert the measured, digital value into the real measured quantity. This formula is called the calibration function. Determining this function is called calibration of the system. Calibration is required, because each system, even each sensor, is different. Therefore, each system reacts slightly different to a measured quantity: it deviates from the calibration curve given in the datasheet.


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Two categories can be used to indicate the deviation sources, static sources and dynamic sources. The static sources can be determined once, while the dynamic sources vary over time, and therefore need to be updated regularly. Static sources can be: 

Manufacturing differences in the sensor



Differences in power supply (every board has a slightly different voltage level)



The offset of the ADC used in the microcontroller board

Dynamic sources can be: 

Temperature



Weather (high and low pressure area's)



General noise sources

If we take the measurement of the pressure as example the step from binary value to voltage and from voltage to pressure can be calibrated relatively well. The calculation of altitude as reference to the pressure is highly dependent on the weather. On a clear day the pressure at ground level is different to the pressure on a rainy day, hence the offset of the measurements will vary significantly. Calibrating a sensor can be done in various ways. A method for calibrating a temperature sensor, for example, would be to place it in an oven together with a pre-calibrated thermometer. Let the temperature of the oven rise slowly and at predefined intervals, note the digital reading of the CanSat and the temperature indicated on the thermometer. With a number of these measurements, a relation between measured temperature and digital reading value can be established.

4.2

Using the transmitter

After the measurements and calculations are made, the next step is transmitting the data to the ground station. During transmission it is important to use a clear and understandable transmission sequence. The transceiver provided with the CanSat kit uses the same type of UART connection as the connection with the USB cable. The difference is the UART port that is used. In case of the transceiver, we use UART port 1: Serial1.begin(19200); // init Serial port for transmitter (default baud rate is 19200) Serial1.println("Transmitting this message"); // sending a message to the transmitter. When making a transmission the data needs to be packaged in a way that can be recognized. This


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identifier is sent it is time to send the variables. During the transmission of the variables it might be a good idea to clearly identify each variable. Serial1.println("T-Minus "); Serial1.print("Analog0: "); Serial1.println(Analog0); Serial1.print("Floating point version of Analog0: "); Serial1.println(Analog0float); Serial1.print("making a calculation: "); Serial1.print(Analog0withcalc); Serial1.println(" equals Analog0 * 2 / 1012"); Serial1.println("");

The communication that is sent using the transmitter can be identical to the transmission made to the USB port. A good practice is to first try to send every calculation using the USB port, before using the transmitter to send all the data. When starting with the transmitter start by just sending an identifier.

4.2.1

Transceiver as ground station

One of the RF boards included in the CanSat kit can be used as a ground station, by using its USB connection. The driver is identical to the driver used for the µC board. The transceiver can be used to receive data on a computer and also to send data from the computer. Similar to the µC board a com port will be created. Any program that can read the com port can be used. The Arduino program can be used to read out the receiver. The downside of Arduino is that it does not allow logging of the received data. As option the program "putty", which can be found on the internet, can be used as it has a logging function.


4.2.2

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Changing the Settings of the transceiver

When using the transmitter for the first time every transmitter is set to a default value: 

Frequency: 432.99MHz



Air baud rate: 19200



Power setting: 13dbm



UART baud rate; 19200

To change the settings the T-Minus RF GUI v1 is used. The program can be found on the USB stick under "programs\Radio module changing settings\T-Minus RF GUI only runs on Windows/T-Minus RF GUI v1.exe". Unfortunately the GUI only works under windows at this time. Before using the program, 3 important steps have to be carried out: 

Install ".net framework 4.5" or newer o

Can be found on internet on the Microsoft website



Connect the transceiver



Start the GUI

If the transceiver is not connected when the program starts an error message might occur. This error occurs when there are no available com ports.


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The GUI as shown in Figure 37 has several options for changing the transceiver settings. Going from top to bottom: 

Select Com Port o

The pull down menu shows a list of the available com ports.

o

To update the list, use the "update list" button. This is automatically done at the start of the program





Check board connection o

Is used to check whether a correct board is connected

o

The answer shows the board and software version of the board

Frequency o



A pull down menu with the available frequencies

Baud rate air o

A pull down menu with the available baud rates for the link between two transceivers



Transmit power o



A pull down menu with the available power settings

Baud rate UART o

The UART baud rate needs to be set equal to the setting on the µC board, defined in the Arduino program



Command information o



Read button o



Reads the settings currently located in the transceiver

Write button o



Shows information about commands that have been send

Writes the current selection in to the transceiver

Read write information box o

Shows whether the read or write option has been succes sful


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5 Building the CanSat Now we have electronics that work but this does not make a CanSat. To complete the CanSat several things are still required: 

Putting all the components of the CanSat together in such a way that they will fit inside the soda can.



Creation of an outer shell to protect the internal components of the CanSat.



The last and most important part is the creation of a parachute required to keep the CanSat working even after landing back on the ground.

5.1

Building the stack

There are many different ways to create a CanSat. For the T-Minus CanSat we decided to place all the PCB's on top of each other. The boards are created in such a way that this is possible. Of course the boards could also be placed in any other direction that fits within the soda can.

Figure 38 possible build of the T-Minus CanSat

When building the stack there are several things to consider. The most important of these is that the CanSat will be shaken violently during launch. This shaking might damage any components that are not connected in a very sturdy manner. The basic idea is that components and wires are not able to move.


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consider are placement of the battery, to allow easy replacement, adding an ON/OFF switch to increase battery life and the placement of extra or other type of antennas. The mechanical components provided with the CanSat kit can be used to create the stack structure. In Figure 39 this stack is shown. The main focus of the structure is guiding the launch and deployment loads. The hook used to connect the parachute is very important. The loads on the parachute can exceed 40G of deceleration requiring a strong connection between the hook and other parts of the can.

Figure 39 possible build of the mechanical components

5.2

The Outer shell

An outer shell is not strictly required, but it is a good thing to create some protection for the internal components. The project is called CanSat, based on a satellite in a soda can. It is however not required to use a soda can as outer shell. The CanSat does need to fit within the size of a soda can. Using a soda can will make sure that this is the case.

5.3

Parachute design

In order to slow down your CanSat you will need some sort device which helps it to land. This can be done in numerous ways, but two types of recovery mechanisms are highlighted in this chapter: 

A drag parachute



A lift parachute

The drag parachute is by far the simplest way to creates drag in order to reduce the speed of a falling object. The most commonly known drag device is a parachute. A parachute is a piece of fabric and cables which create enough aerodynamic drag to slow the object down to a lower descent velocity


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Figure 40: a simple parachute, as used to slow humans down

A lift parachute is much more complex than a drag device. This is basically a system which creates lift by moving through the air. The air moves over and under the cleverly shaped lifting surface which results in a big lifting force and a small drag force. A good example of a lift device would be an aircraft wing or ram air parachute. The big advantage of this type of parachute is that is it potentially steerable, when trimmed correctly. The disadvantage is that they are highly complex to build, difficult to trim and are less reliable in deploying correctly in the air.

Figure 41: a ram-air parachute, as modern parachutists use


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The physics behind the drag parachute and the lift parachute are similar in nature. The formula’s connected to the drag parachute are:

  ⁄    Where: 

Fdrag is the drag force from the parachute



ρ

is the density of air

[N] [kg/m3]

V is the airspeed of the parachute

[m/s]



Cd is the drag coefficient

[-]



S is the surface area of the parachute

[m2]



The cd or drag coefficient is a dimensionless number which depends on the shape of an object. Basically it

is a number which indicates how “easy” air, or any other fluid is flowing around a shape. If the object is very aerodynamic, like an aeroplane or a car, this number is fairly low (for example 0.2). If the shape is not so aerodynamic, such as a simple plate or a parachute shape, the C d will be very high, for example (0.8 or higher). Of course these numbers are empirical and based on a certain area where this drag coefficient is calculated over. For a normal circular parachute the drag coefficient will be in the range of 0.75 over the flat surface of a parachute. The flat surface of a parachute is the surface area when put a parachute flat on a table top. The density of dry air can be calculated using the ideal gas law.



   

Where: is the air density



ρ



p is absolute pressure



Rspecific is the specific gas constant for dry air



The specific gas constant for normal dry air is 287.058



T is absolute temperature at that altitude.

[kg/m3] [Pa]

[J/(kg·K)] [K]

Under normal circumstances the air density at sea level (15°C) is approximately 1.225 kg/m3.


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Figure 42: constant descent velocity: equilibrium between forces

In case of constant descent velocity it can be stated that the weight of the drop mass (or CanSat in this case) + parachute is equal to the drag force of the parachute. This means that the following is true:

  ⁄     Where: 

m is the mass of the total system



g is the gravitational acceleration of 9.80665 m/s2



ρ

[kg] [m/s2]

is the air density

[kg/m3]

V is the airspeed of the parachute

[m/s]



cd is the drag coefficient

[-]



S is the surface area of the parachute



[m2]

By combining these formulas we can calculate how big the parachute should be in order to have the desired descend time. Furthermore, by dimensioning the parachute, you can also predict the impact velocity of your CanSat, by taking the air density ρ as the value of ISA sea-level of 1.225 kg/m3.


5.3.1

Version: 1.0

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Lifting parachute

A lifting parachute is a much more complex device than a normal drag parachute. The device is basically the same as an airplane wing but it is inflated into its correct shape by the incoming air. The wing will generate lift by the air which is flowing around the wing. A small added problem with this lift is that it will come at a small price, namely drag.

Because a lot of formula’s go way further then the scope of this CanSat project and go deep into aerospace engineering. The most important factor is the ratio between lift and drag. This ratio, which is for simple lifting ram-air parachutes around 3 to 5, is also known as the glide ratio. Basically this corresponds with the amount of horizontal distance can be obtained per vertical distance.

Figure 43: the difference between a high glide ratio and a low glide ratio

In order to steer with a lifting parachute some steering-lines can be attached to the leading edge of each side of the wing. When one of these lines is pulled inwards, the wing has more drag on that side than on the other side of the wing. This difference in drag causes the wing to rotate and can therefore be used to steer the wing into the proper directi on. If the parachute is not properly trimmed the wing can stall. This means that the wing will stop flying because the air not flowing smoothly around the wing anymore. Try to trim the wing forward again in order to reduce this stall tendency. It must be noted again that this type of parachute is definitely not recommended for beginners and is very difficult to produce, deploy and fly.


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Figure 44: a CanSat with a ram air lifting parachute

5.4

Launch loads

Most CanSat competitions use a rocket to deploy the CanSat at the desired altitude. This means that the

CanSat is subjected to high accelerations (up to 30 G’s) and vibrations during launch. This has severe consequences on the structural and mechanical design of the CanSat. First of all, the design should be strong. Sufficiently strong to carry 30 times its own weight. Next to that, all connections, both electrical and mechanical, should be able to withstand vibrations. This means that cables need to be supported by the structure, nuts have to be self-locking or secured with loctite or glue, and heavy electronic components have to be glued to the PCB where possible. Make the construction sufficiently stiff, so that it does not deform severely under load.


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Appendix A. Licence information ATMEL Licence

Software running on the Atmel micro controllers is based on the Atmel Software framework. Under the following copy write notice. Copyright (c) 2009-2013 Atmel Corporation. All rights reserved. License Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.



2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.



3. The name of Atmel may not be used to endorse or promote products derived from this software without specific prior written permission.



4. This software may only be redistributed and used in connection with an Atmel microcontroller product.

THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Arduino licence

The Arduino program and information about the program comes from the Arduino website, at "arduino.cc". This information is released by Arduino as "Creative Commons Attribution ShareAlike 3.0". More information on this can be found at "http://creativecommons.org/licenses/by-sa/3.0/legalcode".


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B. T-Minus µC board

Figure 45 The T-Minus Engineering B.V. µC board pin layout

The T-Minus µC board uses an Atmega 2560 micro controller. For more information on this micro controller the datasheet can be found on the Atmel website. Table 3 shows which pin of the board is connected to what pin of the micro controller.


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Table 3 Pin names and numbers of the µC board Arduino digital pin numbers DP0 DP 1 DP 2 DP 3 DP 4 DP 5 DP 6 DP 7 DP 8 DP 9 DP 10 DP 11 DP 12 DP 13 DP 14 DP 15 DP 16 DP 17 DP 18 DP 19 DP 20 DP 21 DP 22 DP 23 DP 24 DP 25 DP 26 DP 27 DP 28 DP 29

Atmel pin number PH0 PH1 PH2 PH3 PH4 PH5 PH6 PH7 PL0 PL1 PL2 PL3 PL4 PL5 PL6 PL7 PA0 PA1 PA2 PA3 PA4 PA5 PA6 PA7 PB3 PB2 PB1 PB0 PD7 PB7

connected to connector

function

Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Digital Onboard LED Onboard LED Onboard LED Onboard LED Onboard LED Onboard LED Onboard LED Onboard LED BUS BUS BUS BUS BUS BUS

digital I/O digital I/O digital I/O digital I/O/ PWM digital I/O/ PWM digital I/O/ PWM digital I/O/ PWM digital I/O digital I/O digital I/O digital I/O digital I/O/ PWM digital I/O/ PWM digital I/O/ PWM digital I/O digital I/O

MISO MOSI SCK /SS T0 OC0A

Arduino digital pin numbers DP 30 DP 31 DP 32 DP 33 DP 34 DP 35 DP 36 DP 37 DP 38 DP 39 DP 40 DP 41 DP 42 DP 43 DP 44 DP 45 DP 46 DP 47 DP 48 DP 49 DP 50 DP 51 DP 52 DP 53 DP 54 DP 55

Atmel pin number PD6 PB5 PD1 PD0 PD2 PD3 PD5 PJ0 PJ1 PJ2 PF0 PF1 PF2 PF3 PK0 PK1 PK2 PK3 PK4 PK5 PK6 PK7 PE2 PE3 PE0 PE1

connected to connector BUS BUS BUS BUS BUS BUS BUS BUS BUS BUS Analog Analog Analog Analog Analog Analog Analog Analog Analog Analog Analog Analog Analog Analog USB USB

function

T1 PWM SDA SCL RXD1 TXD2 XCK1 RXD3 TXD3 XCK3 A8 A9 A10 A11 A0 A1 A2 A3 A4 A5 A6 A7 AIN0 PWM/AIN1 TXD0 RXD0


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C. T-Minus transceivers

The transceiver requires 4 connections to work from an external controller or the use of the USB connector. The use of both connections results in USB mode operation, and negates any data from the UART connection. The board operates from 3.3V to 5.5V when using the 20 pin connector to operate.


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D. Driver installation summary This appendix describes the installation of the proper software to program and communicate with the microcontroller via a computer. The procedure is written for the Microsoft Windows 7 operating system, but a similar method can be followed on other platforms. For the microcontroller board and transceivers to communicate with the computer, the appropriate drivers have to be installed first. These drivers are included in the programs section of the USB stick. First, connect the µC board to a free USB port of the computer. A pop-up will appear in the lower right corner, indicating that the board is connected and that the computer will search for appropriate drivers. Since the drivers are not by default included in the database, the drivers will not be detected automatically; hence they have to be installed manually. To do this, open the device manager (in the start menu, right- click “computer”, click “properties” and then

in the upper part of the left menu, click “Device manager”). You will find that the T -Minus board is in the device list, with an exclamation mark next to it. Right-click the exclamation mark and click “update

driver”. In the window that appears, click the bottom -most option: “search my computer for drivers”. Browse to the USB stick, to the folder programs\windows\T-Minus board driver. Click “ok”. Click “next”. Now, the appropriate driver will be installed.

E. Installing Arduino Now, we want to be able to program the microcontroller. This is done in the Arduino programming environment.

The

Arduino

program

has

to

be

installed.

On

the

USB

stick,

we

go

to

“programs \windows\ Arduino” and start the Arduino installer, which is an executable. This will install the Arduino programming environment onto the computer. The Arduino programming environment can be opened by using the shortcut on the desktop.

Installing T-Minus Variants

The T-Minus board variant is not installed by standard in the Arduino environment. We have to do this manually. We first have to find out where Arduino stores the examples and board configuration files. This is done in the Sketchbook location. We can find it by selecting “File” in the menu bar, followed by

“preferences”. In the screen that appears, select the path indicated in the top textbox and copy it to the clipboard . Now close the Arduino program. Now open a new explorer window, go to the USB stick location and open the file programs\T-Minus files for Arduino.zip. Unzip or extract the content to the sketchbook location .


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program. To select the T-Minus board, go to Tools->board and select the TMinus1 entry. In the menu Tools->Serial Port, select the COM port to which the T-Minus board is connected. Now press the “upload” button:

The status bar at the bottom of the screen should indicate “Compiling…” followed by “Uploading…” and “Upload completed”. This completes the installation of the programming environment for the µC board.


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F. Batteries and power system In order to provide power to your CanSat, you need to have an electrical power system. There are numerous ways to power your CanSat, but the most sensible way is to incorporate a battery. Other options, such as photovoltaic cells (solar cells) can be explored but are outside the scope of this chapter.

Battery types

A battery is a device which consists of one or more electrochemical cells which produce electricity by converting the stored chemical energy into electrical energy. Batteries are available in two types: 

Primary cells or single-use batteries, which are cheap and can be bought in the supermarket or hardware store. The chemical energy in this type of battery is incorporated in the battery at the manufacturing process. This type of battery CANNOT be recharged.

Figure 46: a single use 9V battery, which can be bought at any local supermarket (source AFGA)



Secondary cells or rechargeable batteries, which can be recharged by special charging equipment. It is absolutely necessary to use the proper charging equipment. The use of the improper charging equipment can result in fire and toxic fumes. An example of this type of battery is a lithium polymer battery which can be seen in Figure 47.


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Figure 47: a lithium polymer battery, which is rechargeable with special balanced -charging equipment. (source Wikimedia.org) Advantages and disadvantages

The rechargeable battery has several advantages and disadvantages with respect to a single use battery. It depends on the requirements you have on a battery which battery you will need for your CanSat. Some considerations for choosing a battery type may be: 

A rechargeable battery can obviously be recharged during the project, which could result in a cost saving, because you do not need to buy new single-use batteries all the time.



The energy density of a rechargeable battery is higher than a single use battery. This means that for example 100 grams of rechargeable battery can contain more energy than 100 grams of single use battery. This is a very important factor in aerospace engineering, where every gram counts!



The disadvantage of the rechargeable battery is that you will need special charging equipment to charge your battery. This can be (very) expensive. Charging a battery can be dangerous, so always charge your battery on a non-combustible surface and never let it be unsupervised.



Note: ALWAYS come to the launch site with fully charged batteries, or a fresh single use battery.

Calculations with a battery

The ESA CanSat kit needs voltages between 5.5V and 15V and has a power requirement of approximately 80 mA depending on the operation and the connected sensors. When a device which needs 80 mA is connected to for example a battery of 550 mAh, this means that it can run for



  . Of course, this will just be a rough estimation, since other factors, like


Version: 1.0

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dependent on the amount of current that is consumed. Battery datasheets provide good reference for several types of current loading. The standard CanSat kit is powered by a simple single use 9V primary cell, of which specifications can be found in Figure 48.

Battery tips and tricks

Having a good, stable and reliable voltage supply is absolutely essential for having a good and reliable CanSat. The CanSat electronics will only work when they are supplied with enough power. If the voltage drops only a fraction of a second under the 5.5V, strange things can happen, such as resetting microcontrollers or loss of signal. Make sure that the battery of the CanSat is fixed properly in the CanSat so that the battery leads are not momentarily disconnected when the rocket is accelerating, or the parachute is deployed with a high shock. Other things that could happen is that some subsystems of your CanSat use a lot of power. Due to this power consumption the voltage that the battery supplies to the system drops, which can result for instance in a reset of one or more microcontrollers.


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Figure 48: typical datasheet of a zinc –manganese-dioxide battery, which is supplied by the kit. (source AFGA)

It is definitely not recommended to use the provided battery for flight. It is a simple test-battery to be used just for that: testing the CanSat on the ground.


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G. Datasheets and USB drive content Three datasheets are related to this document. 

MPX4115



LM35



NTC thermistor

This document, its datasheets and the required programs are also located on the USB memory stick. The documents of the memory stick are placed in the following folder structure: 

T-Minus CanSat Kit USB Programs o INSTALATION of T-Minus files for Arduino.txt 



T-Minus files for Arduino.zip



Linux 



Arduino o

arduino-1.0.5-linux32.tgz

o

arduino-1.0.5-linux32.tgz

Mac 

Arduino

arduino-1.0.5-macosx.zip Radio module changing settings T-Minus RF GUI only runs on Windows IMPORTANT info on T-Minus GUI.txt o T-Minus RF GUI v1.exe o Windows o









Arduino



arduino-1.0.5-windows.exe arduino-1.0.5-windows.zip o T-Minus board_driver o

o o o

atmel_devices_cdc.cat atmel_devices_cdc.inf

Documentation 



CanSat kit User Manual.pdf CanSat kit component datasheets LM35.pdf MPX5115.pdf NTC thermistor.pdf Printouts   





component connecting aid.pdf Processor board pin layout.pdf



Processor board pin description.pdf



Document Number: MPX4115 Rev 5, 08/2006

Freescale Semiconductor Technical Data

Integrated Silicon Pressure Sensor Altimeter/Barometer Pressure Sensor On-Chip Signal Conditioned, Temperature Compensated and Calibrated

MPX4115 SERIES OPERATING OVERVIEW INTEGRATED PRESSURE SENSOR 15 to 115kPa (2.18 to 16.7 psi) 0.2 to 4.8 Volts Output

The MPX4115 series is designed to sense absolute air pressure in an altimeter or barometer (BAP) applications. Freescale's BAP sensor integrates on-chip, bipolar op amp circuitry and thin film resistor networks to provide a high level analog output signal and temperature compensation. The small form factor and high reliability of on-chip integration makes the Freescale BAP sensor a logical and economical choice for application designers.

MPX4115A CASE 867-08

Features •

1.5% Maximum Error over 0! to 85!

•

Ideally suited for Microprocessor or Microcontroller-Based Systems

•

Available in Absolute, Differential and Gauge Configurations

•

Durable Epoxy Unibody Element

•

Easy-to-Use Chip Carrier Option MPX4115AP CASE 867B-04

Typical Applications •

Altimeter

•

Baromete ORDERING INFORMATION(1) Device

Options

Case No.

MPX Series Order No.

Marking

Basic Element

Absolute, Element Only

Case 867-08

MPX4115A

MPX4115A

Ported Elements

Absolute, Ported

Case 867B-04

MPX4115AP

MPX4115AP

Absolute, Stove Pipe Port

Case 867E-03

MPX4115AS

MPX4115A

Absolute, Axial Port

Case 867F-03

MPX4115ASX

MPX4115A

1. The MPX4115A BAP Sensor is available in the Basic Element package or with pressure port fittings that provide mounting ease and barbed hose connections.

MPX4115AS CASE 867E-03

MPX4115ASX CASE 867F-03

PIN NUMBERS 1

VOUT(1)

4

N/C(2)

2

GND

5

N/C(2)

3

VS

6

N/C(2)

1. Pin 1 is noted by the notch in the lead. 2. Pins 4, 5, and 6 are internal device connections. Pin 1 is noted by the notch in the Lead. Do not connect to external circuitry or ground.

© Freescale Semiconductor, Inc., 2006. All rights rese rved.

VS

Thin Film Temperature Compensation and Gain Stage #1

Sensing Element

Gain Stage #2 and Ground Reference Shift Circuitry

VOUT

Pins 4, 5, and 6 are NO CONNECTS GND

Figure 1. Integrated Pressure Sensor Schematic Table 1. Maximum Ratings(1) Parametrics

Symbol

Value

Unit

Overpressure(2) (P1 > P2)

Pmax

400

kPa

Burst Pressure (2) (P1 > P2)

Pburst

1000

kPa

Tstg

-40 ! to +125!

!C

T A

-40 ! to +125!

!C

Storage Temperature Operating Temperature 1. TC = 25!C unless otherwise noted.

2. Exposure beyond the specified limits may cause permanent damage or degradation to the device.

MPX4115 SERIES

Table 2. Operating Characteristics (VS = 5.1 Vdc, TA = 25!C unless otherwise noted, P1 > P2 Decoupling circuit shown in Figure 3 required to meet electrical specifications.) Characteristic

Symbol

Min

Typ

Max

Unit

Pressure Range (1)

POP

15

-

115

kPa

Supply Voltage(2)

VS

4.85

5.1

5.35

Vdc

Supply Current

Io

—

7.0

10

mAdc

Minimum Pressure Offset (3) @ VS = 5.1 Volts

(0 to 85 !C)

Voff

0.135

0.204

0.273

Vdc

Full Scale Output(4)

(0 to 85 !C)

VFSO

4.725

4.794

4.863

Vdc

(0 to 85 !C)

VFSS

—

4.59

—

Vdc

(0 to 85 !C)

—

—

—

" 1.5

%VFSS

V/P

—

46

—

mV/kPa

Response Time(7)

tR

—

1.0

—

ms

Output Source Current at Full Scale Output

l o+

—

0.1

—

mAdc

Warm-Up Time(8)

—

—

20

—

mSec

Offset Stability (9)

—

—

" 0.5

—

%VFSS

@ VS = 5.1 Volts Full Scale Span(5)

@ VS = 5.1 Volts Accuracy(6) Sensitivity

1. 1.0kPa (kiloPascal) equals 0.145 psi. 2. Device is ratiometric within this specified excitation range. 3. Offset (Voff ) is defined as the output voltage at the minimum rated pressure. 4. Full Scale Output (VFSO) is defined as the output voltage at the maximum or full rated pressure. 5. Full Scale Span (VFSS) is defined as the algebraic difference between the output voltage at full rated pressure and the output voltage at the minimum rated pressure. 6. Accuracy (error budget) consists of the following: Linearity:Output deviation from a straight line relationship with pressure, using end point method, over the specified pressure range. Temperature Hysteresis:Output deviation at any temperature within the operating temperature range, after the temperature is cycled to and from the minimum or maximum operating temperature points, with zero differential pressure applied. Pressure Hysteresis:Output deviation at any pressure within the specified range, when this pressure is cycled to and from the minimum or maximum rated pressure at 25 !C. TcSpan:Output deviation over the temperature range of 0 ! to 85 !C, relative to 25 !C. TcOffset:Output deviation with minimum pressure applied, over the temperature range of 0 ! to 85!C, relative to 25!C. Variation from Nominal:The variation from nominal values, for Offset or Full Scale Span, as a percent of V FSS at 25!C. 7. Response Time is defined as the time for the incremental change in the output to go from 10% to 90% of its final value when subjected to a specified step change in pressure. 8. Warm-up is defined as the time required for the product to meet the specified output voltage after the Pressure has been stabilized. 9. Offset stability is the product's output deviation when subjected to 1000 hours of Pulsed Pressure, Temperature Cycling with Bias Test.

Table 3. Mechanical Characteristics Characteristic

Symbol

Min

Typ

Max

Unit

Weight, Basic Element (Case 867)

—

—

4.0

—

Grams

Common Mode Line Pressure (1)

—

—

—

690

kPa

1. Common mode pressures beyond what is specified may result in leakage at the case-to-lead interface.

MPX4115 SERIES

Figure 2 illustrates the absolute sensing chip in the basic chip carrier (Case 867). A fluorosilicone gel isolates the die surface and wire bonds from the environment, while allowing the pressure signal to be transmitted to the sensor diaphragm. The MPX4115A series pressure sensor operating characteristics, and internal reliability and qualification tests are based on use of dry air as the pressure media. Media, other than dry air, may have adverse effects on

Fluoro Silicone Gel Die Coat

sensor performance and long-term reliability. Contact the factory for information regarding media compatibility in your application. Figure 4 shows the sensor output signal relative to pressure input. Typical, minimum, and maximum output curves are shown for operation over a temperature range of 0! to 85!C. (The output will sa turate outside of the specified pressure range.)

Stainless Steel Metal Cover

Die

Epoxy Plastic Case

P1 Wire Bond

Lead Frame Absolute Element P2

Sealed Vacuum Reference

Die Bond

Figure 2. Cross-Sectional Diagram (Not to Scale)

+5.0 V

1 OUTPUT

3 1.0 µF

0.01 µF IPS

2

Figure 3. Recommended Power Supply Decoupling. (For output filtering recommendations, please refer to Application Note AN1646.) 5.0 4.5 4.0 3.5 ) s t l o V ( t u p t u O

TRANSFER FUNCTION: Vout = Vs* (.009*P-.095) " Error

MAX

VS = 5.1 Vdc TEMP = 0 to 85 !C

3.0 2.5

TYP

2.0 1.5 1.0 0.5

MIN

0

5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 1 1 2 9 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 1 1 1 1 1

Pressure (ref. to sealed vacuum) in kPa

Figure 4. Output versus Absolute Pressure

MPX4115 SERIES

Transfer Function (MPX4115) Nominal Transfer Value:

Vout = VS (P x 0.009 - 0.095) ± (Pressure Error x Temp. Factor x 0.009 x V S) VS = 5.1 V ± 0.25 Vdc

Temperature Error Band MPX4115A Series

4.0 3.0 Temperature Error Factor

2.0

Temp

Multiplier

- 40 0 to 85 +125

3 1 3

1.0 0.0 -40

-20

0

20

40

60

80

100

120

140

Temperature in C!

Pressure Error Band

9.0 ) a P k ( r o r r E e r u s s e r P

6.0 3.0 0.0

10

20

30 40

50

60 70

80

90 100 110 120

Pressure (in kPa)

-3.0 -6.0 -9.0

Pressure

Error (Max)

15 to 115 (kPa)

± 1.5 (kPa)

MPX4115 SERIES

PACKAGE DIMENSIONS

C R POSITIVE PRESSURE (P1)

M B

-AN PIN 1 SEATING PLANE

1

2

3

4

5

NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. DIMENSION -A- IS INCLUSIVE OF THE MOLD STOP RING. MOLD STOP RING NOT TO EXCEED 16.00 (0.630).

DIM A B C D F G J L M N R S

L

6

-TG

J S

F

STYLE 1: PIN 1. 2. 3. 4. 5. 6.

VOUT GROUND VCC V1 V2 VEX

D 6 PL 0.136 (0.005)

STYLE 2: PIN 1. 2. 3. 4. 5. 6.

OPE N GROUND -VOUT VSUPPLY +VOUT OPEN

M

T A

M

STYLE 3: PIN 1. 2. 3. 4. 5. 6.

OPEN GROUND +VOUT +VSUPPLY -VOUT OPEN

CASE 867-08 ISSUE N BASIC ELEMENT (A, D)

CASE 867B-04 ISSUE G PRESSURE SIDE PORTED (AP, GP)

MPX4115 SERIES

INCHES MILLIMETERS MIN MAX MIN MAX 0.595 0.630 15.11 16.00 0.514 0.534 13.06 13.56 0.200 0.220 5.08 5.59 0.027 0.033 0.68 0.84 0.048 0.064 1.22 1.63 0.100 BSC 2.54 BSC 0.014 0.016 0.36 0.40 0.695 0.725 17.65 18.42 30˚ NOM 30˚ NOM 0.475 0.495 12.07 12.57 0.430 0.450 10.92 11.43 0.090 0.105 2.29 2.66

PACKAGE DIMENSIONS

-B-

NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH.

A

C

DIM A B C D E F G J K N S V

V PIN 1

PORT #1 POSITIVE PRESSURE (P1)

6

K

4

3

2

1

S

J N

5

G F

E

STYLE 1:

D 6 PL

-T-

INCHES MIN MAX 0.690 0.720 0.245 0.255 0.780 0.820 0.027 0.033 0.178 0.186 0.048 0.064 0.100 BSC 0.014 0.016 0.345 0.375 0.300 0.310 0.220 0.240 0.182 0.194

0.13 (0.005)

M

T B

PIN 1. 2. 3. 4. 5. 6.

M

MILLIMETERS MIN MAX 17.53 18.28 6.22 6.48 19.81 20.82 0.69 0.84 4.52 4.72 1.22 1.63 2.54 BSC 0.36 0.41 8.76 9.53 7.62 7.87 5.59 6.10 4.62 4.93

V OUT GROUND VCC V1 V2 VEX

CASE 867E-03 ISSUE D PRESSURE SIDE PORTED (AS, GS)

–T– C

A E

–Q–

U

NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. INCHES DIM A B C

N

V

D

B R PIN 1

PORT #1 POSITIVE PRESSURE (P1)

E F G J N

0.25 (0.010)

M

T Q

M

5

4

3

2

P

1

S K

Q R S U V

J 0.13 (0.005)

M

T P

S

D 6 PL Q S

K

–P– 6

MIN

G

F

MILLIMETERS

MAX

1 .0 80 1 .1 20 0 .7 40 0 .7 60 0 .6 30 0 .6 50 0.027 0.03 3 0.160 0.18 0 0.048 0.06 4 0 .1 00 B SC 0.014 0.01 6 0.220 0.24 0 0.070 0.08 0 0.150 0.16 0 0.150 0.16 0 0 .4 40 0 .4 60 0 . 69 5 0 .7 25 0 .8 40 0 .8 60 0.182 0.19 4

MIN

MAX

2 7. 43 2 8. 45 1 8. 80 1 9. 30 1 6. 00 1 6. 51 0.6 8 0. 84 4.0 6 4. 57 1.2 2 1. 63 2 .5 4 B SC 0.3 6 0. 41 5.5 9 6. 10 1.7 8 2. 03 3.8 1 4. 06 3.8 1 4. 06 11 .1 8 11 .6 8 1 7. 65 1 8. 42 2 1. 34 2 1. 84 4.6 2 4. 93

STYLE 1: PIN 1. VOUT 2. GROUND 3. VCC 4. V1 5. V2 6. VEX

CASE 867F-03 ISSUE D PRESSURE SIDE PORTED (ASX, GSX)

MPX4115 SERIES

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LM35

LM35 Precision Centigrade Temperature Sensors

Literature Number: SNIS159B

November 2000

LM35 Precision Centigrade Temperature Sensors General Description The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in ˚ Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of ± 1 ⁄ 4˚C at room temperature and ±3 ⁄ 4˚C over a full −55 to +150˚C temperature range. Low cost is assured by trimming and calibration at the wafer level. The LM35’s low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and minus supplies. As it draws only 60 µA from its supply, it has very low self-heating, less than 0.1˚C in still air. The LM35 is rated to operate over a −55˚ to +150˚C temperature range, while the LM35C is rated for a −40˚ to +110˚C range (−10˚ with improved accuracy). The LM35 series is available pack-

aged in hermetic TO-46 transistor packages, while the LM35C, LM35CA, and LM35D are also available in the plastic TO-92 transistor package. The LM35D is also available in an 8-lead surface mount small outline package and a plastic TO-220 package.

Features Calibrated directly in ˚ Celsius (Centigrade) Linear + 10.0 mV/˚C scale factor n 0.5˚C accuracy guaranteeable (at +25˚C) n Rated for full −55˚ to +150˚C range n Suitable for remote applications n Low cost due to wafer-level trimming n Operates from 4 to 30 volts n Less than 60 µA current drain n Low self-heating, 0.08˚C in still air 1 n Nonlinearity only ± ⁄ 4˚C typical n Low impedance output, 0.1 Ω for 1 mA load n n

Typical Applications

DS005516-4 DS005516-3

FIGURE 1. Basic Centigrade Temperature Sensor (+2˚C to +150˚C)

Choose R1 = −VS /50 µA V OUT =+1,500 mV at +150˚C = +250 mV at +25˚C = −550 mV at −55˚C

FIGURE 2. Full-Range Centigrade Temperature Sensor

L M 3 5 P r e c i s i o n C e n t i g r a d e T e m p e r a t u r e S e n s o r s

5 3 M L

Connection Diagrams TO-46 Metal Can Package*

SO-8 Small Outline Molded Package

DS005516-1

*Case is connected to negative pin (GND)

DS005516-21

N.C. = No Connection

Order Number LM35H, LM35AH, LM35CH, LM35CAH or LM35DH See NS Package Number H03H

Top View Order Number LM35DM See NS Package Number M08A

TO-92 Plastic Package

TO-220 Plastic Package*

DS005516-2

Order Number LM35CZ, LM35CAZ or LM35DZ See NS Package Number Z03A

DS005516-24

*Tab is connected to the negative pin (GND). Note: The LM35DT pinout is different than the discontinued LM35DP.

Order Number LM35DT See NS Package Number TA03F

Absolute Maximum Ratings (Note 10)

TO-92 and TO-220 Package, (Soldering, 10 seconds) 260˚C SO Package (Note 12) Vapor Phase (60 seconds) 215˚C Infrared (15 seconds) 220˚C ESD Susceptibility (Note 11) 2500V Specified Operating Temperature Range: T MIN to T MAX (Note 2) LM35, LM35A −55˚C to +150˚C LM35C, LM35CA −40˚C to +110˚C LM35D 0˚C to +100˚C

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Output Voltage Output Current Storage Temp.; TO-46 Package, TO-92 Package, SO-8 Package, TO-220 Package, Lead Temp.: TO-46 Package, (Soldering, 10 seconds)

+35V to −0.2V +6V to −1.0V 10 mA −60˚C −60˚C −65˚C −65˚C

to to to to

+180˚C +150˚C +150˚C +150˚C

300˚C

Electrical Characteristics (Notes 1, 6)

LM35A Parameter

Conditions Typical

Design

Limit

Limit

(Note 4)

(Note 5)

±0.5

T MIN ≤TA≤TMAX T MIN ≤TA≤TMAX

+10.0

+9.9,

T A =+25˚C

(Note 7)

T A =−10˚C T A =T MAX T A =T MIN

Nonlinearity

Tested

±0.2 ±0.3 ±0.4 ±0.4 ± 0.18

Accuracy

LM35CA

±1.0 ±1.0

± 0.35

Typical

±0.2 ±0.3 ±0.4 ±0.4 ± 0.15

Tested

Design

Units

Limit

Limit

(Max.)

(Note 4)

(Note 5)

±0.5

˚C

±1.0

˚C

±1.0

˚C

±1.5 ± 0.3

˚C ˚C

(Note 8) Sensor Gain

+10.0

+9.9,

+10.1

(Average Slope)

±0.4 ± 0.5 ±0.01 ± 0.02

Load Regulation

T A =+25˚C

(Note 3) 0≤IL≤1 mA

T MIN ≤TA≤TMAX

Line Regulation

T A =+25˚C

(Note 3)

4V≤V S ≤30V

Quiescent Current

V S =+5V, +25˚C

56

(Note 9)

V S =+5V

105

V S =+30V, +25˚C

56.2

V S =+30V

105.5

mV/˚C

+10.1

±1.0

± 3.0 ±0.05

± 0.1 67

±0.4 ± 0.5 ± 0.01 ± 0.02 56

131 68 1.0

mV/mA

±0.05

mV/V

± 0.1

67

mV/V µA

114

µA

68

91.5 0.2

mV/mA

± 3.0

91 56.2

133

±1.0

µA

116

Change of

4V≤VS≤30V, +25˚C

0.2

Quiescent Current

4V≤V S ≤30V

0.5

2.0

0.5

2.0

+0.39

+0.5

+0.39

+0.5

+1.5

+2.0

+1.5

+2.0

µA

1.0

µA µA

(Note 3) Temperature

µA/˚C

Coefficient of Quiescent Current Minimum Temperature

In circuit of

for Rated Accuracy

Figure 1, IL =0

Long Term Stability

T J =T MAX, for 1000 hours

±0.08

± 0.08

˚C ˚C

L M 3 5

5 3 M L

Electrical Characteristics (Notes 1, 6)

LM35 Parameter

Conditions

Tested

Design

Limit

Limit

(Note 4)

(Note 5)

Typical Accuracy,

T A =+25˚C

LM35, LM35C

T A =−10˚C

(Note 7)

T A =T MAX

±0.4 ±0.5 ±0.8 ±0.8

T A =T MIN Accuracy, LM35D (Note 7)

LM35C, LM35D

±1.0 ±1.5 ±1.5

T A =+25˚C TA =T MAX TA =T MIN

Nonlinearity

T MIN ≤TA≤TMAX

± 0.3

T MIN ≤TA≤TMAX

+10.0

± 0.5

Typical

± 0.4 ± 0.5 ± 0.8 ± 0.8 ± 0.6 ± 0.9 ± 0.9 ± 0.2

Tested

Design

Units

Limit

Limit

(Max.)

(Note 4)

(Note 5)

±1.0

˚C

±1.5 ±1.5 ±2.0

˚C ˚C ˚C

±1.5

˚C

±2.0 ±2.0 ± 0.5

˚C ˚C ˚C

(Note 8) Sensor Gain

+9.8,

+10.0

+9.8,

+10.2

(Average Slope)

±0.4 ± 0.5 ±0.01 ± 0.02

±2.0

V S =+5V, +25˚C

56

80

V S =+5V

105

V S =+30V, +25˚C

56.2

V S =+30V

105.5

Load Regulation

T A =+25˚C

(Note 3) 0≤IL≤1 mA

T MIN≤TA≤TMAX

Line Regulation

T A =+25˚C

(Note 3)

4V≤V S≤30V

Quiescent Current (Note 9)

mV/˚C

+10.2

± 5.0 ±0.1

± 0.2 158 82

± 0.4 ± 0.5 ±0.01 ± 0.02

±2.0

56

80

161 2.0

± 5.0

mV/mA mV/V

± 0.2

mV/V µA

138

µA

82

91.5 0.2

±0.1

91 56.2

mV/mA

µA

141

Change of

4V≤VS≤30V, +25˚C

0.2

Quiescent Current

4V≤V S≤30V

0.5

3.0

0.5

3.0

+0.39

+0.7

+0.39

+0.7

+1.5

+2.0

+1.5

+2.0

µA

2.0

µA µA

(Note 3) Temperature

µA/˚C

Coefficient of Quiescent Current Minimum Temperature

In circuit of

for Rated Accuracy

Figure 1 , IL =0

Long Term Stability

T J =T MAX, for

±0.08

±0.08

˚C ˚C

1000 hours Note 1: Unless otherwise noted, these specifications apply: −55˚C≤TJ≤+150˚C for the LM35 and LM35A; −40˚≤TJ≤+110˚C for the LM35C and LM35CA; and 0˚≤TJ≤+100˚C for the LM35D. V S =+5Vdc and ILOAD=50 µA, in the circuit of Figure 2 . These specifications also apply from +2˚C to T MAX in the circuit of Figure 1. Specifications in boldface apply over the full rated temperature range. Note 2: Thermal resistance of the TO-46 package is 400˚C/W, junction to ambient, and 24˚C/W junction to case. Thermal resistance of the TO-92 package is 180˚C/W junction to ambient. Thermal resistance of the small outline molded package is 220˚C/W junction to ambient. Thermal resistance of the TO-220 package is 90˚C/W junction to ambient. For additional thermal resistance information see table in the Applications section. Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output due to heating effects can be computed by multiplying the internal dissipation by the thermal resistance. Note 4: Tested Limits are guaranteed and 100% tested in production. Note 5: Design Limits are guaranteed (but not 100% production tested) over the indicated temperature and supply voltage ranges. These limits are not used to calculate outgoing quality levels. Note 6: Specifications in boldface apply over the full rated temperature range. Note 7: Accuracy is defined as the error between the output voltage and 10mv/˚C times the device’s case temperature, at specified conditions of voltage, current, and temperature (expressed in ˚C). Note 8: Nonlinearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the device’s rated temperature range. Note 9: Quiescent current is defined in the circuit of Figure 1. Note 10: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating the device beyond its rated operating conditions. See Note 1. Note 11: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Note 12: See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in a current National Semiconductor Linear Data Book for other methods of soldering surface mount devices.

L M 3 5

Typical Performance Characteristics Thermal Resistance Junction to Air

Thermal Response in Still Air

Thermal Time Constant

DS005516-26 DS005516-25

Thermal Response in Stirred Oil Bath

DS005516-27

Minimum Supply Voltage vs. Temperature

Quiescent Current vs. Temperature (In Circuit of Figure 1.)

DS005516-29

DS005516-28

DS005516-30

Quiescent Current vs. Temperature (In Circuit of Figure 2 .)

Accuracy vs. Temperature (Guaranteed)

Accuracy vs. Temperature (Guaranteed)

DS005516-32 DS005516-31

DS005516-33

5 3 M L

Typical Performance Characteristics (Continued) Noise Voltage

Start-Up Response

DS005516-34

DS005516-35

Applications

The TO-46 metal package can also be soldered to a metal surface or pipe without damage. Of course, in that case the V− terminal of the circuit will be grounded to that metal. Alternatively, the LM35 can be mounted inside a sealed-end metal tube, and can then be dipped into a bath or screwed into a threaded hole in a tank. As with any IC, the LM35 and accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is especially true if the circuit may operate at cold temperatures where condensation can occur. Printed-circuit coatings and varnishes such as Humiseal and epoxy paints or dips are often used to insure that moisture cannot corrode the LM35 or its connections.

The LM35 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued or cemented to a surface and its temperature will be within about 0.01˚C of the surface temperature. This presumes that the ambient air temperature is almost the same as the surface temperature; if the air temperature were much higher or lower than the surface temperature, the actual temperature of the LM35 die would be at an intermediate temperature between the surface temperature and the air temperature. This is expecially true for the TO-92 plastic package, where the copper leads are the principal thermal path to carry heat into the device, so its temperature might be closer to the air temperature than to the surface temperature.

These devices are sometimes soldered to a small light-weight heat fin, to decrease the thermal time constant and speed up the response in slowly-moving air. On the other hand, a small thermal mass may be added to the sensor, to give the steadiest reading despite small deviations in the air temperature.

To minimize this problem, be sure that the wiring to the LM35, as it leaves the device, is held at the same temperature as the surface of interest. The easiest way to do this is to cover up these wires with a bead of epoxy which will insure that the leads and wires are all at the same temperature as the surface, and that the LM35 die’s temperature will not be affected by the air temperature.

Temperature Rise of LM35 Due To Self-heating (Thermal Resistance,θJA) TO-46,

TO-46*,

TO-92,

TO-92**,

SO-8

SO-8**

TO-220

no heat sink

small heat fin

no heat sink

small heat fin

no heat sink

small heat fin

no heat sink

Still air

400˚C/W

100˚C/W

180˚C/W

140˚C/W

220˚C/W

110˚C/W

90˚C/W

Moving air

100˚C/W

40˚C/W

90˚C/W

70˚C/W

105˚C/W

90˚C/W

26˚C/W

Still oil

100˚C/W

40˚C/W

90˚C/W

70˚C/W

Stirred oil

50˚C/W

30˚C/W

45˚C/W

40˚C/W

(Clamped to metal, Infinite heat sink)

(24˚C/W)

(55˚C/W)

*Wakefield type 201, or 1" disc of 0.020" sheet brass, soldered to case, or similar. **TO-92 and SO-8 packages glued and leads soldered to 1" square of 1/16" printed circuit board with 2 oz. foil or similar.

L M 3 5

Typical Applications

DS005516-19

FIGURE 3. LM35 with Decoupling from Capacitive Load

DS005516-6

FIGURE 6. Two-Wire Remote Temperature Sensor (Output Referred to Ground) DS005516-20

FIGURE 4. LM35 with R-C Damper CAPACITIVE LOADS Like most micropower circuits, the LM35 has a limited ability to drive heavy capacitive loads. The LM35 by itself is able to drive 50 pf without special precautions. If heavier loads are anticipated, it is easy to isolate or decouple the load with a resistor; see Figure 3 . Or you can improve the tolerance of capacitance with a series R-C damper from output to ground; see Figure 4 . When the LM35 is applied with a 200Ω load resistor as shown in Figure 5 , Figure 6 or Figure 8 it is relatively immune to wiring capacitance because the capacitance forms a bypass from ground to input, not on the output. However, as with any linear circuit connected to wires in a hostile environment, its performance can be affected adversely by intense electromagnetic sources such as relays, radio transmitters, motors with arcing brushes, SCR transients, etc, as its wiring can act as a receiving antenna and its internal junctions can act as rectifiers. For best results in such cases, a bypass capacitor from VIN to ground and a series R-C damper such as 75Ω in series with 0.2 or 1 µF from output to ground are often useful. These are shown in Figure 13 , Figure 14 , and Figure 16 .

DS005516-7

FIGURE 7. Temperature Sensor, Single Supply, −55˚ to +150˚C

DS005516-8

FIGURE 8. Two-Wire Remote Temperature Sensor (Output Referred to Ground)

DS005516-5

FIGURE 5. Two-Wire Remote Temperature Sensor (Grounded Sensor)

DS005516-9

FIGURE 9. 4-To-20 mA Current Source (0˚C to +100˚C)

5 3 M L

Typical Applications (Continued)

DS005516-11

FIGURE 11. Centigrade Thermometer (Analog Meter)

DS005516-10

FIGURE 10. Fahrenheit Thermometer DS005516-12

FIGURE 12. Fahrenheit ThermometerExpanded Scale Thermometer (50˚ to 80˚ Fahrenheit, for Example Shown)

DS005516-13

FIGURE 13. Temperature To Digital Converter (Serial Output) (+128˚C Full Scale)

DS005516-14

FIGURE 14. Temperature To Digital Converter (Parallel TRI-STATE™ Outputs for Standard Data Bus to µP Interface) (128˚C Full Scale)

L M 3 5

Typical Applications (Continued)

DS005516-16

=1% or 2% film resistor Trim RB for VB =3.075V Trim RC for VC =1.955V Trim RA for VA =0.075V + 100mV/˚C x T ambient Example, VA=2.275V at 22˚C *

FIGURE 15. Bar-Graph Temperature Display (Dot Mode)

DS005516-15

FIGURE 16. LM35 With Voltage-To-Frequency Converter And Isolated Output (2˚C to +150˚C; 20 Hz to 1500 Hz)

5 3 M L

Block Diagram

DS005516-23

Physical Dimensions inches (millimeters) unless otherwise noted

TO-46 Metal Can Package (H) Order Number LM35H, LM35AH, LM35CH, LM35CAH, or LM35DH NS Package Number H03H

SO-8 Molded Small Outline Package (M) Order Number LM35DM NS Package Number M08A

L M 3 5

5 3 M L


Power Package TO-220 (T) Order Number LM35DT NS Package Number TA03F

(Continued)


L M 3 5 P r e c i s i o n C e n t i g r a d e T e m p e r a t u r e

(Continued)

S e n s o r s

TO-92 Plastic Package (Z) Order Number LM35CZ, LM35CAZ or LM35DZ NS Package Number Z03A

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2381 640 10.../NTCLE101E3...SB0 Vishay BCcomponents

NTC Thermistors, Radial Leaded Special Accuracy FEATURES •

Excellent accuracy between 25 °C and 85 °C

•

High stability over a long life

•

Old part number was 2322 640 10...

•

Compliant to RoHS directive 2002/95/EC and in accordance to WEEE 2002/96/EC

APPLICATIONS •

Temperature measurement, sensing and control

QUICK REFERENCE DATA VALUE

PARAMETER

Resistance at 25

°C (1)

DESCRIPTION

4.7 kΩ to 100 kΩ

Temperature measurement accuracy (between 25 °C and 85 °C)

These thermistors have a negative temperature coefficient. The device consists of a chip with two tin-plated copper leads. It is grey lacquered and not insulated. These thermistors are very accurate (± 0.5 °C) over a trajectory from 25 °C to 85 °C.

± 0.5 °C

Climatic category

40/125/56

Maximum dissipation

250 mW

Dissipation factor

7 mW/K

δ

(for information only)

Response time (for information only) (2)

1.2 s

Thermal time constant (for information only)

11 s

τ

PACKAGING

The thermistors are packed in cardboard boxes, each box contains 500 units.

Operating temperature range: at zero dissipation (continuously)

- 40 °C to + 125 °C

at maximum dissipation

0 °C to + 55 °C

Weight

MARKING

≈ 0.22 g

Grey lacquered body.

Notes (1)

For values of nominal resistance value and tolerance at intermediate temperatures; see resistance values tables.

(2)

Response time in silicone oil MS 200/50. This is the time needed for the sensor to reach 63.2 % of the total temperature difference when subjected to a temperature change from 25 °C in air to 85 °C in oil.

MOUNTING

By soldering in any position.

ELECTRICAL DATA AND ORDERING INFORMATION R 25

ΔR 25 / R25

R 85

ΔR 85 / R85

(Ω)

(Ω)

(%)

B25/85 (K)

ΔB/B

(%)

4700

2.19

503.1

1.58

3977

0.75

10472

472SB0

10 000

2.19

1070

1.58

3977

0.75

10103

103SB0

47 000

2.23

4721

1.64

4090

1.5

10473

473SB0

100 000

2.29

9496

1.72

4190

1.5

10104

104SB0

(%)

CATALOG NUMBER SAP MATERIAL NO. 2381 640 ..... NTCLE101E3......

2381 640 10.../NTCLE101E3...SB0 NTC Thermistors, Radial Leaded Special Accuracy DIMENSIONS in millimeters

Vishay BCcomponents

TOLERANCE CURVE 3 max.

3.3 ± 0.5

∆T (K)

1.0

5 max.

0.5

2±1

0

2.54

- 40 - 25

0

25

40

60

85

110 125 T(°C)

- 0.5

17 min.

- 1.0

Ø 0.6

RESISTANCE VALUES AT INTERMEDIATE VALUES with R 25 at 4.7 kΩ and 10 kΩ R T

Toper (°C)

R T / R25

TCR (%/K)

- 40 - 35 - 30 - 25 - 20 - 15 - 10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150

33.21 23.99 17.52 12.93 9.636 7.250 5.505 4.216 3.255 2.534 1.987 1.570 1.249 1.000 0.8059 0.6535 0.5330 0.4372 0.3605 0.2989 0.2490 0.2084 0.1753 0.1481 0.1256 0.1070 0.09154 0.07860 0.06773 0.05858 0.05083 0.04426 0.03866 0.03387 0.02977 0.02624 0.02319 0.02055 0.01826

6.57 6.36 6.15 5.95 5.76 5.58 5.40 5.24 5.08 4.92 4.78 4.64 4.50 4.37 4.25 4.13 4.02 3.91 3.80 3.70 3.60 3.51 3.42 3.33 3.25 3.16 3.09 3.01 2.94 2.87 2.80 2.73 2.67 2.61 2.55 2.49 2.43 2.38 2.33

(k Ω) 2381 640 10472 NTCLE101E3472SB0 156.1 112.8 82.35 60.77 45.30 34.08 25.87 19.81 15.30 11.91 9.340 7.378 5.869 4.700 3.788 3.072 2.505 2.055 1.694 1.405 1.170 0.9797 0.8239 0.6960 0.5905 0.5031 0.4303 0.3694 0.3183 0.2753 0.2389 0.2080 0.1817 0.1592 0.1399 0.1233 0.1090 0.0966 0.0858

2381 640 10103 NTCLE101E3103SB0 332.1000 240.0 175.2 129.3 96.36 72.50 55.05 42.16 32.56 25.34 19.87 15.70 12.49 10.00 8.059 6.535 5.330 4.372 3.606 2.989 2.490 2.084 1.753 1.481 1.256 1.070 0.9154 0.7860 0.6773 0.5858 0.5083 0.4426 0.3866 0.3387 0.2977 0.2624 0.2319 0.2055 0.1826

2381 640 10.../NTCLE101E3...SB0 Vishay BCcomponents

NTC Thermistors, Radial Leaded Special Accuracy

RESISTANCE VALUES AT INTERMEDIATE VALUES with R 25 at 47 k Ω R T

(k Ω)

Toper (°C)

R T / R25

TCR (%/K)

- 40

33.81

6.55

1589

- 35

24.50

6.34

1151

- 30

17.93

6.15

842.8

- 25

13.25

5.96

622.6

- 20

9.875

5.78

464.1

- 15

7.425

5.61

349.0

- 10

5.630

5.45

264.6

-5

4.304

5.29

202.3

0

3.315

5.14

155.8

5

2.573

4.99

120.9

10

2.011

4.85

94.53

15

1.583

4.72

74.40

20

1.254

4.59

58.95

25

1.000

4.46

47.00

30

0.8024

4.34

37.71

35

0.6474

4.23

30.43

40

0.5255

4.12

24.70

45

0.4288

4.01

20.15

50

0.3518

3.91

16.53

55

0.2901

3.81

13.63

60

0.2403

3.71

11.30

65

0.2001

3.62

9.404

70

0.1674

3.53

7.865

75

0.1406

3.44

6.607

80

0.1186

3.36

5.573

85

0.1004

3.28

4.721

90

0.08542

3.20

4.015

95

0.07292

3.13

3.427

100

0.06248

3.06

2.936

105

0.05372

2.98

2.525

110

0.04635

2.92

2.179

115

0.04013

2.85

1.886

120

0.03485

2.79

1.638

125

0.03037

2.73

1.427

130

0.02654

2.67

1.247

135

0.02326

2.61

1.093

140

0.02044

2.55

0.9608

145

0.01802

2.50

0.8468

150

0.01592

2.44

0.7483

2381 640 10473 NTCLE101E3473SB0

2381 640 10.../NTCLE101E3...SB0 NTC Thermistors, Radial Leaded Special Accuracy

Vishay BCcomponents

RESISTANCE VALUES AT INTERMEDIATE VALUES with R 25 at 100 k Ω R T

(k Ω)

Toper (°C)

R T / R25

TCR (%/K)

- 40

36.66

6.70

3666

- 35

26.38

6.49

2638

- 30

19.17

6.29

1917

- 25

14.06

6.10

1406

- 20

10.41

5.92

1041

- 15

7.779

5.74

777.9

- 10

5.861

5.57

586.1

-5

4.453

5.41

445.3

0

3.409

5.26

340.9

5

2.631

5.11

263.1

10

2.044

4.97

204.4

15

1.600

4.83

160.0

20

1.261

4.70

126.1

25

1.000

4.57

100.0

30

0.7981

4.45

79.81

35

0.6408

4.35

64.08

40

0.5175

4.22

51.74

45

0.4202

4.11

42.02

50

0.3431

4.00

34.31

55

0.2816

3.90

28.16

60

0.2322

3.80

23.22

65

0.1925

3.71

19.25

70

0.1602

3.62

16.03

75

0.1340

3.53

13.40

80

0.1126

3.45

11.26

85

0.09496

3.36

9.496

90

0.08042

3.28

8.042

95

0.06837

3.21

6.837

100

0.05835

3.13

5.835

105

0.04998

3.06

4.998

110

0.04296

2.99

4.296

115

0.03705

2.92

3.705

120

0.03206

2.86

3.206

125

0.02783

2.80

2.783

2381 640 10104 NTCLE101E3104SB0

CanSat Kit User Manual V2014

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