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.