The document describes a line following robot with obstacle detection capabilities. It uses a PIC microcontroller, IR sensors, motors and other components. The robot follows a black line but can detect and stop for objects in its path, then continue once the object is removed. It has applications in automated delivery systems, factories and tours. The hardware and software work together to sense the line and navigate corners while avoiding obstacles.

1. Line Following Robot with
Obstacle Detection

2. Objectives
 Improve knowledge of robotics as well as
microcontroller programming and electronic circuit
design and construction.
 Construct a robot which capable of following a black
line.
 Stop within safe distance of an object in its path.
 Automatically continue when object moved.
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3. Application area
 Deliver Mail within an office building to another
building.
 Industrial automated equipment carriers.
 Automated cars.
 Tour guides in museums and other similar
applications.

4. Main Components
 PIC Microcontroller
 Voltage Comparator
 Motor Driver IC
 Voltage Regulator
 Motor
 IR Transmitter
 IR Receiver Sensors
 Battery
 Programmer

5. HARDWARE DESCRIPTION

6. PIC Microcontroller 16F72
 Program Memory : 3.5 KB
 Speed: 20 MHz clock
 Instruction cycle: 200 ns instruction cycle
 RAM: 128 Bytes
 PIN Count: 28
 No of I/O: 22
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7. Microcontroller
 It is a smaller computer
 Has on-chip RAM, ROM, I/O ports...
RAM ROM
I/O
Port
Timer
Serial
COM
Port
Microcontroller
CPU
A single chip

8. MOTORS
The motors are run at 6v, so an effective speed of 65 rpm is
achieved, with a considerable increase in torque.

9. Voltage Comparator LM324
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10. Motor Driver H-Bridge L293D
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11. IR TRANSMITTER ( EMITTING DIODE)
 The IR LED emitting infrared light is put on in the
transmitting unit. IR or VISIBLE light is emitted from
the emitter.
 This emitted light strikes the surface and gets
reflected back. If the surface is white, more
intensity of light gets reflected and for black surface
very less intensity of light is reflected.
IR RECEIVER (PHOTODETECTOR)
Used to detect the intensity of light reflected. The
corresponding analog voltage is induced based on
the intensity of reflected light, which further
compared by comparator and output send as 0 or 1.
IR Transmitter & Receiver

12. Regulator IC 7805
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 A voltage regulator is an electrical
regulator designed to automatically maintain
a constant voltage level.
It converts a positive voltage (7-29V) to
+5 volts.
Heat sink provided in the center to release
heat generated due to drop across the IC.
 Input voltage of about 5 to 18 V is given,
Ground is 0 V and regulated output of +5V.

13. Battery
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14. Programmer
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15. WORKING PROCEDURE

16. Block Diagram

17. Black Line Sensor Line Follower
© 2015 EV3Lessons.com, Last edit
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1
Sensor 1 on White
Sensor 2 on White
Go forward
Sensor 1 on Black
Sensor 2 on White
Turn left
Sensor 1 on White
Sensor 2 on Black
Turn right
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1
2
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18. WORKING PRINCIPLE
When a sensor is on the black line it reads 0 and when it is on the bright surface it reads
1.
When left sensor comes in white(for black line
tracer) region then right motor stops while left
motor continue to move so that right turn takes
place and robot returns on white line.
First sensor which is to the right will become
low as that sensor will be facing the black line and
the remaining sensors response will be high. i.e.
the right wheel is held constant and the left wheel
is made to move freely until the response from the
middle sensor becomes low .
When right sensor comes in white region then
left motor stops while right motor continue to
move so that left turn takes place and robot returns
on white line.

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The middle sensor will always be on the line and
as the line is black in color, it will not reflect the
emitted radiation back and the response of the sensor
will be low and the response of the remaining two
sensors will be high as they will be on the bright
surface. When both sensors are on black line then
robot moves forward.
If all the three sensors will be on brighter surface
then they all will be high and as no line is detected,
robot move in a circular motion until line is found.
WORKING PRINCIPLE

20. VARIOUS TRACKS
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21. Software requirements
 MikroC for writing Program
and compiled to generate
machine file.
 Proteus for Simulating the
circuit.
 PIC Kit for input the program
files to Microcontroller.

22. LIMITATIONS
 Calibration is difficult and it is not easy to set a
perfect value.
 The steering mechanism is not easily
implemented in huge vehicles and impossible
for non-electric vehicles (petrol powered).
 Few curves are not made efficiently, and must
be avoided.
 External IR source is affected the sensor.
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23. FUTURE SCOPE
 Software control of the line type (dark or
light) to make automatic detection
possible.
 “Obstacle detecting sensors” to avoid
physical obstacles and continue on the
line.
 Distance sensing and position logging &
find the shortest path.
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