Building a Line Following Robot

Figure 1 

This self-operating robot utilizes 6 optical sensors mounted at the front in order to follow a line drawn on a surface.

An ATmega8 microcontroller is being used to control the line following robot which uses a lithium coin cell for its power. In order to avoid accidental resets, the AVR and motors are powered by two coin cells separately. Depending on the line conditions in order not to lose line due to friction, the speed of the motors is adjusted using pulse width modulation (PWM). The whole device weighs around 15g and the dimensions are 45×33×12.5mm only with an average speed of 53cm/s.

The two driving wheels and a free wheel are 3 points that hold up the line following robot. A 5mm diameter ball bearing attached loosely refers to the free wheel while a 7mm diameter ball bearing and a rubber tire make up the driving wheels. The two vibration motors used for cellular phone or pager are being used to drive the driving wheels.

The ambient light is canceled using pulse light which is suitable or arrayed sensors that scan in sequence so that the interference from next sensor is avoided.

Rest of the project