Line Following Robot

This Project Line Following Autonomous Robot is based on 8 bit Microcontroller. 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. Microcontroller gets the signals from the infrared sensors and it drives the motors according to the sensor inputs. Two stepper motors are used to drive the robot.

THEORY OF OPERATION-:  How to sense a black line The sensors used for the project are Reflective Object Sensors, 0PB710F that are already ready in the Electronic Lab. The single sensor consists of an infrared emitting diode and a NPN Darlington phototransistor. When a light emitted from the diode is reflected off an object and back into the phototransistor, output current is produced, depending on the amount of infrared light, which triggers the base current of the phototransistor. In my case, the amount of light reflected off a black line is much less than that of a white background, so we can detect the black line somehow by measuring the current. (This current is converted to voltage.)

ii) How to control a DC motor
Instead of applying a constant voltage across a DC motor, we repeat switching on and off the motor with a fixed voltage (Vcc) applied to the motor. This is done by sending a train of PWM (Pulse Width Modulation) pulses to a power MOSFET in order to turn it on and off. Then, the motor sees the average voltage while it depends on duty cycle of PWM pulses. The speed of rotation is proportion to this average voltage.
By PWM method, it’s easier to control the DC motor than by directly controlling the voltage across it. All we have to do is to modulate pulse width, in ord


Project idea by: HBeonLabs, Greater Noida, India

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53 Responses to “Line Following Robot”

  1. elsabath k raju

    will you please mail me the details…… i am looking for making a line sensor…….

  2. Sean Botes


    I am an Electrical Engineering student and I am planning on building a Line Following Robot similar to the one you have presented here. If it is at all possible, can you please send me information regarding the circuit diagram as I wish to use it as a basis for my project.

    Thank you.

  3. yatheendraanath

    I’m intersted to do this project can u send the circuit diagram for this.

  4. Sir, I am very much interested in doing this project, so can you please send me the further details of the circuit diagram and other important details required for buying it.

  5. sir i m interested in this project.. plz send me more details of it…

  6. S.Mekhala

    sir i wud lik to work out dis project…pls send me necessary details

  7. HBonlabs are talented, gifted engineers.
    I have no doubt in your work.
    The line following Robot is great.
    I need the circuit diagram and source code to build one.

    Kindly send to my mail [email protected]

  8. prakash

    sir i m interested in this project.. plz send me details of it…

  9. priyanka

    sir i m interested in this project.. plz send me more details of it.

  10. sir please send me the details of the project…including the circuits and mechanical parts used in it…reply soon

  11. kindly send me specifications and all info about project like circiut diagram and hardware used


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