1. Synopsis
on
“LINE FOLLOWER ROBOT”
Submitted in partial fulfillment of the requirement for the award of the degree
of
Bachelor of Technology
In
Electronics & Communication Engineering
Submitted by:
A Ritesh Kumar (5309243)
B Vijender Singh (5309255)
C Rahul Sharma (5309239)
Department of Electronics & Communication Engineering
Hindustan Institute of technology & management
Dheen – 133202 (Ambala)

2. Introduction
This Project, Line Following Autonomous Robot is based on 8 bit Microcontroller AT89C51.
This Robot follows the black line which is drawn over the white surface or it follows the white
line which is drawn over the black surface. The infrared sensors are used to sense the line.
When the infrared signal falls on the white surface, it gets reflected and if it falls on the black
surface, it is not reflected.
This principle is used to scan the Lines for the Robot. All the above systems are controlled by
the Microcontroller. In our project we are using the popular 8 bit microcontroller AT89C51. It
is a 40 pin microcontroller. The Microcontroller AT89C51 is used to control the motors. It gets
the signals from the infrared sensors and it drives the motors according to the sensor inputs.
Two DC geared motors are used to drive the robot in forward, left or right direction.

3. Block Diagram
The robot uses IR sensors to sense the line, an array of 8 IR LEDs (Tx) and sensors (Rx),
facing
the ground has been used in this setup. The output of the sensors is an analog signal which
depends on the amount of light reflected back, this analog signal is given to the comparator to
produce 0s and 1s which are then fed to the uC.
L4 L3 L2 L1 R1 R2 R3 R4 Left Center Right Sensor Array
Starting from the center, the sensors on the left are named L1, L2, L3, L4.
Block diagram of line follower robot
Circuit Diagram
Here we are using pins P1.0 and P1.4 for taking the inputs from the IR sensors after being
amplified by LM324.
Microcontroller is used for the processing of the input data and controlling the output devices
depending upon the input. We are taking input from the sensors, which is used to control the
motion of the motors. The motors at the output section are used to run the Line Follower robot
in a particular direction.
The input to the microcontroller is fed as below:

4. Pin 1_0 Left sensor status
Pin1_4 Right sensor status
This input is used to drive the left motor and the right motor through L293(motor deriver IC).
For this, we need to provide six signals from microcontroller to L293, three for each motor, as
below:
P2_0 Enable(En1) signal for left motor
P2_1 Switch1(In1) signal for Left motor
P2_2 Switch2 (In2)signal for Left motor
P2_3 Enable(En2) signal for Right motor
P2_4 Switch1(In3) signal for Right motor
P2_5 Switch2(In4) signal for Right motor
Circuit diagram of line follower robot

5. List of component
 Microcontroller
 Dtmf
 Sensor
 Register
 Power supply
 L293D moter driver
 Motor
 Compartor LM324
 Wheel
 Headphone for input

6. Applications of Line Follower Robot
1. It can act as maze solver. Basically it follows a line, therefore it can be used in mining where
the robots are used to find the way out of the mine.
2. If we implement a robotic arm along with the line follower then it can be used to pick and
place the objects in its way and can be very useful in our day to day life.
3. Apparatus to control the automatic placing of material along a junction between surfaces
with reference to the form and position of the junction including a tool controllably movable to
deposit material progressively along the junction in response to a control signal.
4. An imager linked to the movement of the tool to produce an image of the surfaces.
5. By modifying the position of the sensors, same principle can be used in obstacle avoidance
and edge detection.

7. Applications of Line Follower Robot
1. It can act as maze solver. Basically it follows a line, therefore it can be used in mining where
the robots are used to find the way out of the mine.
2. If we implement a robotic arm along with the line follower then it can be used to pick and
place the objects in its way and can be very useful in our day to day life.
3. Apparatus to control the automatic placing of material along a junction between surfaces
with reference to the form and position of the junction including a tool controllably movable to
deposit material progressively along the junction in response to a control signal.
4. An imager linked to the movement of the tool to produce an image of the surfaces.
5. By modifying the position of the sensors, same principle can be used in obstacle avoidance
and edge detection.