Arduino Line Follower Robot

Line follower Robot is one of the first robots that beginners and students would get their first robotic experience with. In this project, we have designed a simple Line Follower Robot using Arduino and some other components

Circuit Diagram

Components Required

  • Arduino UNO (or Arduino Nano)

  • L293D Motor Driver IC

  • Geared Motors x 2

  • Robot Chassis

  • IR Sensor Module x 2

  • Black Tape (Electrical Insulation Tape)

  • Connecting Wires

  • Power supply

Block Diagram


Sensors (IR Sensor): We have used IR Sensor Module as the line detecting sensor for the project. It consists of an IR LED and a Photo diode and some other components like comparator, LED etc

.As mentioned earlier, we have used a pre – assembled IR Sensor. In case you do not have one, you can make your own sensor using the following circuit.


The working of the IR Sensor and its scope in this project will be explained in the actual working of the Line Follower Robot.

Controller (Arduino UNO): Arduino UNO is the main controller in the project. The data from the sensors (IR Sensors) will be given to Arduino and it gives corresponding signals to the Motor Driver IC.

Motor Driver (L293D): L293D Motor Driver IC is used in this project to drive the motors of the robot. It receives signals from Arduino based on the information from the IR Sensors.

Note: The power supply to the motors must be given from the motor driver IC. Hence, choose the appropriate power supply which is sufficient for all the components including the motors.

Motors (Geared Motors): We have used two geared motors at the rear of the line follower robot. These motors provide more torque than normal motors and can be used for carrying some load as well.

Working of Arduino Line Follower Robot

In this project, we have designed an Arduino based Line Follower Robot. The working of the project is pretty simple: detect the black line on the surface and move along that line. The detailed working is explained here.

As mentioned in the block diagram, we need sensors to detect the line. For line detection logic, we used two IR Sensors, which consists of IR LED and Photodiode. They are placed in a reflective way i.e. side – by – side so that whenever they come in to proximity of a reflective surface, the light emitted by IR LED will be detected by Photo diode.

The following image shows the working of a typical IR Sensor (IR LED – Photodiode pair) in front of a light coloured surface and a black surface. As the reflectance of the light coloured surface is high, the infrared light emitted by IR LED will be maximum reflected and will be detected by the Photodiode.

In case of black surface, which has a low reflectance, the light gets completely absorbed by the black surface and doesn’t reach the photodiode.

Using the same principle, we will setup the IR Sensors on the Line Follower Robot such that the two IR Sensors are on the either side of the black line on the floor. The setup is shown below.

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