Post on 10-Jul-2015
description
With ATMega8 µc
Introduction This robot is designed to continuously
follow a black line painted on a bright surface or a white line on a dark surface and take the turns along with the line automatically.
Hardware Components Required Microcontroller development board (ATMega8)
IR Sensor
Comparator (LM358)
DC motor
Motor driver IC (L293D)
Wheels
Power adopter
ATMega8 Development Board
IR Sensors IR sensors give output by receiving the reflected rays
transmitted by the transmitting diode.
If the surface is black, the transmitted
ray will be absorbed and will not be
received and if the surface is white then
receiver will get the reflected ray and generate output.
IR Sensor Circuit
Motor Driver IC (L293D) It is required to supply sufficient
current to motors as microcontrollers can’t supply that much current.
It is a dual H-Bridge motormeans it can drive two DC motors simultaneously in both
clockwise and anticlockwise direction.
Its input terminals are controlledby the microcontroller.It also includes the protection circuit against back EMF.
Block Diagram
IR Sensor 1
IR Sensor 2
Comparator
Comparator
Variable DC voltage
Variable DC voltage
Microcontroller
Motor with
wheel
Motor with
wheel
Motor Driver IC (L293D)
Overview
IR sensors
Chassis Board
AT Mega8 µc
Comparator(LM358)
Voltage regulator IC
Wheel attached
with motor shaft
DC Motor
Description It works with the signal generated by the sensors.
To follow black line, sensors are mounted in frontof robot keeping black line in between them.
Each sensor has a motor associated with it. If itgets the reflected light(means sensors are facingbright background), the comparator sends logic 1to microcontroller and vice versa.
CONTI…. The program loaded into microcontroller takes the
decision of switching any motor ON or OFF according to the inputs coming from the comparators connected after each sensor.
The robot turns in the direction of the sensor detecting the black line, for this microcontroller turns ON only the motor opposite to that sensor.