[Greg] has been doing a great job updating DIY Live. The latest entry details a line following robot. These bots are quite common, but Greg provides really thorough coverage of all of the details involved. His particular design features two separate sensors and when the robot reaches the end of the line it will reverse, retracing its steps. He’s got wiring schematics for the h-bridge and other components. He admits that PIC programming is a topic too broad for one post, but he does discuss a few of the necessary logic chunks involved.