This slide was made for partial fulfillment of engineering project by students of the department of electrical and electronics engineering Kathmandu University, Nepal.

1. Prabin Dawadi (22007)
Ashish K C (22011)
Sanjay Kumar Jayswal(22040)
Ram Bikesh Sah(22050)
Jigyashu Verma(22058)
Supervisor
Kamala Gajurel
Project coordinator
Diwakar Bista
LINE FOLLOWING ROBOT USING COMBINATIONAL LOGIC
Engineering Project (EEEG 212)
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2. Introduction
❖ This Robot is designed to follow the black line on a white
background.
❖ This robot is based on detecting the path by using the IR
sensor receiver pair.
❖ It is an automatic robot which follows a predefined path.
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3. Objectives
❖ To make an automatic line following robot which
follows black line.
❖ It must be reliable.
❖ The robot must be insensitive of the factors such as
lighting and noise.
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4. LIMITATION
 Can only follow predefined path.
 Cannot be controlled manually.
 IR receiver can malfunction due to the rays from sunlight.
 Slow speed and instability on different line thickness or hard
angles.

5. ADVANTAGES
 Robot movement is automatic.
 It can be used for long distance applications.
 Can be used non-commercial and industrial automations.
 Simplicity in building.

6. MECHANICAL DESIGN

7. BLOCK DIAGRAM
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8. Components Used
❖IR Module
❖DC motor
❖Comparator (AP358)
❖IC L293D
❖Caster Wheel
❖Potentiometer
❖Voltage Regulator
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9. IR MODULE
➢ The reverse current in a photodiode is directly proportional to the intensity of
light falling in it.
➢ If we have white surface it reflects the light and it will sensed by the receiver,
similarly if we have black surface it absorbs the light and receiver can not sense
light

10. ❖ The IR Sensor-Single is a general purpose proximity sensor. Here we use it for
path detection. The module consist of a IR emitter and IR receiver pair. The
high precision IR receiver always detects a IR signal.
❖ The module consists of AP358 comparator IC. The output of sensor is high
whenever it receives IR frequency and low otherwise. The on-board LED
indicator helps user to check status of the sensor without using any additional
hardware.The sensitivity can be tuned by the use of a potentiometer.

11. DC Motor
❖ The motor that we used in this project rotates approximately at 100 rpm at an
input voltage level of 6-12V.
❖ Two motors along with wheels are used at the two sides of the robot such that
they do not deflect much from the path and have a better stability and
performance.
❖ Moreover a castor wheel is also used for making jerkless movement in sharp
turnings.

12. Comparator
❖ Operational amplifier is used as an comparator for comparing the potential
developed across two terminals of the photodiode with the reference voltage.
❖ Reference voltage is set by the potentiometer and can be adjusted manually as
per the requirements in different application cases.

13. IC L293D
❖ This motor driver IC allows dc motor to drive on either direction. It is a 16 pin IC
which can control a set of two dc motors simultaneously in any direction.
❖ The supply voltage is given separately to the IC for driving the motors according to
the outputs from the IR sensor-receiver pair.

14. CIRCUIT DIAGRAM
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15. Direction Display Circuit
❖ Positive terminal of each motors is taken as an input for displaying the direction
of the vehicle.
❖ When both the motors stop a sign of steady state ‘S’ is displayed when both are
moving ‘F’ is displayed to indicate forward movement and when the robot is
turning in the direction corresponding direction either ‘L’ or ‘R’ is displayed
depending on which direction the robot turns.

16. Direction Display Circuit
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17. Input First Input Second Display
0 0 S (Stop)
0 1 R (Right)
1 0 L (left)
1 1 F (Forward)

18. Methodology
❖When both IR sensor detects white surface it follows a straight path.
❖When both IR sensor pair detect black surface it stops.
❖When left IR sensor detects white surface and right one detects black then it
turns right until both the sensors are over white surface.
❖When right IR sensor detects white surface and the left detects black then then
it turns left until both sensors detects high.
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19. CONCLUSION
 Studied and implemented the Line following robot using
combinational logic.
 Study of the different components and their
implementation has been done.
 It can be used for various purpose such as industries,
research purpose , etc.

20. GANTT CHART

21. THANK YOU !!!
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