A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. A proximity sensor often emits an electromagnetic field of infrared for instance and looks for changes in the field or return signal.

 

Introduction Path Follower Robot

(See in figure 1)

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Concept of working of Path follower is related to light. We use here the behavior of light at black and white surface. When light fall on a white surface it is almost full reflected and in case of black surface light is completely absorbed. This behavior of light is used in building a path follower robot.

 

In this arduino based Path follower robot we have used IR Transmitters and IR receivers also called photo diodes. They are used for sending and receiving light. IR transmits infrared lights. When infrared rays falls on white surface, it’s reflected back and catched by photodiodes which generates some voltage changes. When IR light falls on a black surface, light is absorb by the black surface and no rays are reflected back, thus photo diode does not receive any light or rays.

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when sensor senses white surface then arduino gets 1 as input and when senses black line arduino gets 0 as input.

 

Explanation of Circuit Diagram

(See in figure 2)

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The Path follower robot can be divided into 3 Part which is 1)sensor, 2)control, 3)driver.

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1).Sensor:

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This contains IR diodes, potentiometer, Comparator (Op-Amp) and LED’s. Potentiometer is used for setting reference voltage at comparator’s one terminal and IR sensors are used to sense the line and provide a change in voltage at comparator’s second terminal. Then comparator compares both voltages and generates a digital signal at output. 

 

Working of Path Follower Robot

(See in figure 3)

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Path follower robot senses black line by using sensor and then sends the signal to arduino. Then arduino drives the motor according to sensors' output.

 

 

Here in this project we are using two IR sensor modules namely left sensor and right sensor. When both left and right sensor senses white then robot move forward.

 

 

• If left sensor comes on black line then robot turn left side.

• If right sensor sense black line then robot turn right side until both sensor comes at white surface. When white surface comes robot starts moving on forward again.

• If both sensors comes on black line, robot stops.

 

Upload code in Arduino UNO

 

To download code click the available link.