PID line follower
This is a project that ive made in order to take part at the Athens Digital Week 2010. Its line follower and maze solver vehicle.
It can sense and follow any dark line in a bright background, such as an electrical tape.
To do this it has 6 IR LED/phototransistor pairs facing down. When the sensor is over the black line the ir from the led is absorved from the line and when the ir is on a bright/white surface the ir get reflected back, so by measuring this values you always know if a sensor is on the black line or not.
In order to give the right commands to the motors for the navigation, it uses a simple PID controller.