The line follower robot is basically designed to follow a black line on a white surface.The entire hardware of this simple line follower robot using arduino can be divided into three parts. The sensor, arduino board and the motor driver circuit.

Setting up the circuit.

  • First of all remember that each LED and LDR has its own characteristics.
  • Carefully measure the voltage across each LDRs in both scenarios (on white surface and black).
  • A lot of parameters like individual LDR/LED characteristics, ambient light, clearance between sensor and surface etc may affect the result.
  • Get in to your own reference point for the program. In my case it was 945 but you may get a different value.
  • Use a separate power supply unit for powering the motors. Anything above 100mA will be hard for the USB port.
  • The motors used here are 9V/30RPM DC bow motors. If such a configuration is not available, choose the closest one.
  • While soldering up the sensor module, the gap between the two LED/LDR pairs must be selected according to the width of the black line. In my case it was 2cm.
  • Clearance of the sensor from the ground was around 1cm in my case.
  • The sensor LEDs used were 4mm bright green LEDs.
  • The sensor LDRs used were general purpose LDRs.