Remote Surveillance Vehicle

ANUBHAV KUMAR(9102346) RITESH SHARMA(9102298)

INTRODUCTION Conventionally, wireless-controlled robots use RF circuits,which have the drawbacks of limited working range, limited frequency range and limited control. Use of a mobile phone for robotic control can overcome these limitations. It provides the advantages of robust control, working range as large as the coverage area of the service provider,no interference with other controllers and up to twelve controls.

Project overview

In this project, the robot is controlled by a mobilephone 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.

Project overview

The robot perceives this DTMF tone with the help ofthe phone stacked in the robot. The received tone is processed by the ATmega8535 microcontroller with the help of DTMF decoder MT8870.

The decoder decodes the DTMF tone into itsequivalent binary digit and this binary number is sent to the microcontroller.

Project overview The microcontroller is pre-programmed to take a

decision for any given 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 the 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

Project Overview The camera and micro-phone mounted on the robot

will give the detailed information of where the robot is and who is around. The signal is then transmitted to the observer via audio/video transmitter-receiver. The metaldetector circuit mounted on the robot

detects any metal object around it and transmits the signal wirelessly.

Illustration

Block diagram representation

Schematic Diagram:

List of components used Atmega AVR8535 Microcontroller

DTMF Decoder IC- MT8870 DC motors,Motor Driver IC-LM293D Piezoelectric Buzzer

Metal detector IR Sensor,LDR Sensors Two mobile phones,one is stacked on the robot Two 9v batteries,voltage dropper ICs-7805 Camera RF Transmitter,Receiver module

DTMF MODULE IC MT8870

DTMF Decoder Module(MT8870)Dual Tone Frequency Modulation

DTMF Module

DTMF DECODER & BCD TO BINARY CONVERTER MODULE DTMF Dual Tone Multiple Frequency Resultant signal of two tones at the same time for any

key pressed f(t) = Asin(2**fa*t) + Bsin(2**fb*t)

WHAT IS DTMF?When you press a button in the telephone set keypad, a connection is made that generates a resultant signal of two tones at the same time. These two tones are taken from a row frequency and a column frequency. The resultant frequency signal is called "Dual Tone Multiple Frequency". These tones are identical and unique. A DTMF signal is the algebraic sum of two different audio frequencies, and can be expressed as follows: f(t) = A0sin(2**fa*t) + B0sin(2**fb*t) + ........... ------->(1)Where fa and fb are two different audio frequencies with A and B as their peak amplitudes and f as the resultant DTMF signal. fa belongs to the low frequency group and fb belongs to the high frequency group.

The amplitudes of the two sine waves should be such that (0.7 < (A/B) < 0.9)V -------->(2) The frequencies are chosen such that they are not the harmonics of each other. The frequencies associated with various keys on the keypad are shown in figure. When we send these DTMF signals to the telephone exchange through cables, the servers in the telephone exchange identifies these signals and makes the connection to the person you are calling. When you press the digit 5 in the keypad it generates a resultant tone signal which is made up of frequencies 770Hz and 1336Hz. Pressing digit 8 will produce the tone taken from tones 852Hz and 1336Hz. In both the cases, the column frequency 1336 Hz is the same. These signals are digital signals which are symmetrical with the sinusoidal wave.

METAL DETECTOR

Description The metal detector circuit implemented on the bot

will sense the metal objects,landmines that would come on the path of the bot. The metal detector circuit we are going to implement on bread-board The circuit layout is presented here.

Metal Detector Circuit

DescriptionThis is a simple single chip metal detector circuit based on IC CS209A from the Cherry Semiconductors. A 100uH coil is used to sense the presence of metal. The IC CS209A has a built in oscillator circuit and the coil L1 forms a part of its external LC circuit which determines the frequency of oscillation. The inductance of the coil change in the presence of metals and the resultant change in oscillation is demodulated to create an alarm. The LED gives a visual indication too. This circuit can sense metals up to a distance of few inches.

Control with MCU chip is designed to control two This As the MCUS port are notDC motors.There are 2 i/p & 2 o/p pins for each motors

powerful enough to drive DC motors directly,so we need some kind of drivers. A very easy and safe is to use L293D chips.It is a 16 pin chip.The pin configuration are as follows:

H bridge

H-Bridge An H bridge is built with four switches (solid-state or

mechanical). When the switches S1 and S2 (according to the first figure) are closed (and S2 and S1 are open) a positive voltage will be applied across the motor and the robot will move forward. By opening S1 and S2 switches and closing S2 and S1 switches, this voltage is reversed, allowing reverse operation of the motor.

Circuit / Mother Board

DETAILS OF ATMEGA8535c40 pin package32 pins are used for the 4 ports.8 channel 10 bit resolution ADC

Inbuilt I2C, SPI, UART features Connections for clock crystal.

16K Bytes of ISP Flash512 Bytes EEPROM, 1K Byte SRAM

Mother Board MB107010 Configuration16x2/16x1 LCD :RS RW E D5 D6 D7 D8 Port C0 Port C1 Port C2 Port C4 Port C5 Port C6 Port C7

Switch(Active low):S1 S2 S3 S4 Port A4 Port A5 Port A6 Port A7

LED interface (Active High):RED LED1 RED LED2 RED LED3 RED LED4 Port C4 Port C5 Port C6 Port C7

ISP:MO MI SCK RST GND Master Out Slave in Master in Slave out Serial clock Reset Ground Port B5 Port B6 Port B7 Reset Ground

ADC:PA0 to PA7

Motor Driver:M0 M1 M2 M3 M4 M5 M6 M7 Port B0 Port B1 Port B2 Port B3 Port D4 Port D5 Port D6 Port D7

BUZZER :(Active High)

Port C3

Sensors:PA0 to PA7 PB0 to PB7

RS232:R Receiver - PD0 T Transmitter - PD1 G Ground