TABLE OF CONTENTS
1. CHAPTER.1 TECHNICAL DETAILS OF THE PROJECTS. INTRODUCTION.
2. CHAPTER.2 PROJECT OVERVIEW.
3. CHAPTER.3 CIRCUIT & COMPONENTS DESCRIPTION. CIRCUIT & INTERFACING DESCRIPTION.
4. REFERENCE
CHAPTER.1
Technical details of the Projects Origin of the Proposal In most college ragging becomes most popular issue.Various steps are taken by government & college management to stop this cruel activity, but all in vain due to lack of staff members in large space of college campus. Colleges are situated in space of hectares, so it is almost impossible to look after the fresher. Presently, college has made anti ragging squad, but still college campus unable to properly avoid this crucial task. To overcome this problem we get an idea Cellphone-Controlled Robot. It helps to capture culprit candidate who involves in unfair activity. GSM technology provides large range of working areas. Due to this feature we can operate this device over large range of areas in college campus. In Law enforcement and military engagements because of many reasons, CellphoneControlled Robot is used. The exposures to hazards are mitigated to the person who operates the vehicle from the location of relative safety. They are used by many police department bombsquads to defuse or detonate explosives.
Objectives
To
improve our militants security at LOC by getting
information about opponent.
Remote controlled vehicles are used in Law enforcement and military engagements because of many reasons. The exposures to hazards aremitigated to the person who operates the vehicle from the location of relative safety. They are used by many police department bomb-squads to defuse or detonate explosives. Current Unmanned Aerial Vehicles (UAVs) can hover around possible targets until they are positively identified before releasing their pay load of weaponry. Backpack sized UAVs will provide ground troops with over the horizon surveillance capabilities.
To
achieve ‘ragging free environment’ in college campus.
Presently, college has made anti ragging squad, but still college campus unable to properly avoid this crucial task.
To
insure the safe areas in mines.
With the help of Cellphone-Controlled Robot, we can predict the areas where the explosion can occur, by the application of sound tracking webcam.
Mobile Controlled ROBOT Using DTMF Technology
Introduction What is a Mobile controlled DTMF ROBOT?
DTMF Mobile ROBOT is a machine that can be that makes a call to the mobile phone attached to the robot. In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call. This tone is called "Dual Tone Multiple-Frequency" (DTMF) tone. The robot perceives this DTMF tone with the help of the phone stacked on the robot. The received tone is processed by the microcontroller with the help of DTMF decoder. The microcontroller then transmits the signal to the motor driver ICs to operate the motors & our robot starts moving.
Why build a DTMF ROBOT?
Conventionally, Wireless-controlled robots use rf circuits,which have the drawbacks of limited working range, limited frequency range and the limited control.Use of a mobile phone for robotic control can overcome these limitations.It provides the advantage of robust control,working range as large as the coverage area of the service provider,no interference with other controllers . Although the appearance and the capabilities of robots vary vastly,all robots share the feature of a mechanical, movable structure under some form of control. The Control of robot involves three distinct phases: perception, processing and action. Generally,the preceptors are sensors mounted on the robot, processing is done by the on-board microcontroller or processor,
CHAPTER.2 POJECT OVERVIEW
In this project the robot, is controlled by a mobile phone that makes call to the mobile phone attached to the robot in the course of the call, if any button is pressed control corresponding to the button pressed is heard at the other end of the call. This tone is called dual tone multi frequency tone (DTMF) robot receives this DTMF tone with the help of phone stacked in the robot.The received tone is processed by the atmega16 microcontroller with the help of DTMF decoder MT8870 the decoder decodes the DTMF tone in to its equivalent binary digit and this binary number is send to the microcontroller.The microcontroller is preprogrammed to take a decision for any give input and outputs its decision to motor drivers in order to drive the motors for forward or backward motion or a turn. The mobile that makes a call to the mobile phone stacked in robot acts as a remote. So this simple robotic project does not require the construction of receiver and transmitter units. DTMF signaling is used for telephone signaling over the line in the voice-frequency band to the call switching centre.The version of DTMF used for telephone tone dialing is known as „Touch-Tone.‟DTMF assigns a specific frequency (consisting of two separate tones) to each key so that it can easily be identified by the electronic circuit. The signal generated by the DTMF encoder is a direct algebraic summation, in real time, of the amplitudes of two sine (cosine) waves of different frequencies, i.e., pressing „5‟ will send a tone made by adding 1336 Hz and 770 Hz to the other end of the mobile. The tone and assignments in a DTMF system shown below
Figures shows the block diagram and circuit diagram of the microcontroller- based robot. The important components of this robot are DTMF decoder, Microcontroller . An MT8870 series DTMF decoder is used here. All types of the mt8870 series use digital counting techniques to detect and decode all the sixteen DTMF tone pairs in to a four bit code output. The built -in dual tone rejection circuit eliminated the need for pre- filtering. When the input signal given at pin2 (IN-) single ended input configuration is recognized to be effective, the correct four bit decode signal of the DTMF tone is transferred to Q1 (pin11) through Q4(pin14) outputs. The ATMEGA 16 is a low power, 8 bit, CMOS microcontroller based on the AVR enhanced RISC architecture. It provides the following feature: 16kb of in system programmable flash memory with read write capabilities, 512bytes of EEPROM, 1KB SRAM, 32 general purpose input/output lines. 32 general purpose working registers. All the 32 registers are directly connected to the arithmetic logic unit, allowing two independent registers to be accessed in one signal instruction executed in one clock cycle. The resulting architecture is more code efficient. Outputs from port pins PD0 through PD3 and PD7 of the microcontroller are fed to inputs IN1 through IN4 and enable pins (EN1 and EN2) of motor driver L293d respectively, to drive geared motors. the notations are : ic1 - mt8870 ic2 - atmega16 ic3 - l293d ic4 - cd7004 r1,r2 - 100k resistances r3 - 330k resistances r4-r8 - 10k resistances
c1- 0.47 micro farad capacitor c2,c3,c5,c6 - 22pfarad capacitor c4 - 0.1micro farad capacitor xtal1 - 3.57 MHz crystal xtal2 - 12mhz crystal s1 - push to on switch m1,m2 - 6v 50rpm motor batt- 6v
DTMF Tone The DTMF technique outputs distinct representation of 16 common alphanumeric characters (0-9, A-D, *, #) on the telephone. The lowest frequency used is 697Hz and the highest frequency used is 1633Hz, as shown in Table 1.
Table 1: DTMF Keypad.
FREQUENCY
1209 HZ
1336 HZ
1477 HZ
1633 HZ
697 Hz
1
2
3
A
770 Hz
4
5
6
B
852 Hz
7
8
9
C
941 Hz
*
0
#
D
The DTMF keypad is arranged such that each row will have its own unique tone frequency and also each column will have its own unique tone frequency. Above is a representation of the
typical DTMF keypad and the associated row/column frequencies. By pressing a key, for example 5, will generate a dual tone consisting of 770 Hz for the low group and 1336 Hz for the high group.
DTMF Decoder The MT-8870 is a DTMF Receiver that integrates both band split filter and decoder functions into a single 18-pin DIP or SOIC package. It is manufactured using CMOS process technology. The MT-8870 offers low power consumption (35 mW max) and precise data handling.
Fig. 2 Pin configuration of MT-8870
Its filter section uses switched capacitor technology for both the high and low group filters and for dial tone rejection. Its decoder uses digital counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit code. External component count is minimized by provision of an on-chip differential input amplifier, clock generator, and latched tri-state interface bus. Minimal external components required includes a low-cost 3.579545 MHz color burst crystal, a timing resistor, and a timing capacitor. The filter section is used for separation of the low-group and high group tones and it is achieved by applying the DTMF signal to the inputs of two sixth order switched capacitor band pass filters, the bandwidths of which corresponds to the low and high group frequencies. The filter section also incorporates notches at 350 and 440 Hz for exceptional dial tone rejection. Each filter output is followed by a single order switched capacitor filter section which smoothes
the signals prior to limiting. Limiting is performed by high-gain comparators which are provided with hysteresis to prevent detection of unwanted low-level signals. The outputs of the comparators provide full rail logic swings at the frequencies of the incoming DTMF signals. Following the filter section is a decoder employing digital counting techniques to determine the frequencies of the incoming tones and to verify that they correspond to the standard DTMF frequencies
CHAPTER.3 CIRCUIT & INTREFACING DESCRIPTION
The circuit diagram oh DTMF ROBO is shown in the figure above. In the circuit IC‟s MT8870 & 74LS04N form the DTMF decoder section with its all components,where IC MT8870 converts the output of mobile into digital binery signal & IC 74LS04N boosts the output of MT8870 and gives it to MCU.While L293D is motor driver IC which runs the motors, in the ROBO these three IC‟S are used beside the MCU. The description of its all subunits is as following on the next page:
POWER SUPPLY UNIT (+6V) Power supplies are designed to convert high voltage AC mains electricity to a suitable low voltage supply for electronics circuits and other devices. A power supply can by broken down into a series of blocks, each of which performs a particular function.
For a 6V regulated supply :
Each of the block has its own function as described below Transformer – steps down high voltage AC mains to low voltage AC. Rectifier – converts AC to DC, but the DC output is varying. Smoothing – smooths the DC from varying greatly to a small ripple. Regulator – eliminates ripple by setting DC output to a fixed voltage.
Motor Driver Circuit L293D is a dual H-Bridge motor driver. So with one IC, two DC motors can be interfaced which can be controlled in both clockwise and counter clockwise directions and its direction of motion can also be fixed. The four I/O‟s can be used to connect upto four DC motors. L293D has output current of 600mA and peak output current of 1.2A per channel. Moreover for the protection of the circuit from back EMF, output diodes are included within the IC. The output supply (VCC2) has a wide range from 4.5V to 36V, which has made L293D a best choice for DC motor driver. The name "H-Bridge" is derived from the actual shape of the switching circuit which controls the motion of the motor. It is also known as "Full Bridge" By using two motors the robot can be moved in any direction. This Steering mechanism of the robot is called differential drive
REFERENCE
Analog Edge, “A Quick Sine Wave Generator,” http://www.national.com/nationaledge/jun04/article.html Dallas Semiconductor, “Digitally Controlled Sine-Wave Generator, http://www.maxim-ic.com/appnotes.cfm/appnote_number/2081 Instructions, Parts List, and Schematic. Operational Amplifier Function Generator, CK103 – Opamp Function Generator, October 2005. http://electronickits.com/kit/complete/meas/ck102.pdf Datasheet, UAF42AP, Burr-Brown (Texas Instruments) Universal Active Filter, http://focus.ti.com/lit/ds/symlink/uaf42.pdf . Burr-Brown Corporation, Texas Instruments, Inc. (1991, 2001). Filter42 [Computer program]. UAF42 Design Program. Tucson, AZ: Applications Engineering. (Application Program No. AB-035) http://focus.ti.com/docs/toolsw/folders/print/filter42.html
http://en.wikipedia.org/wiki/Dual-tone_multi-frequency
http://en.wikipedia.org
