[sanddrag]

Thinking about this, yes optical mice are cool but what came before them? Ball mice! It may not be practical for all games (like climbing a step) but for a game like 2002's Zone Zeal, maybe you could just stick a ball and a couple wheels under the robot. Think Technokats 2003 Ball robot, but maybe 1/4-1/3 the size and instead of motors powering the little wheels there would be shaft encoders hooked to the little wheels. Yeah, that would work, at least on a flat field. Make a cradle in the center of your robot and put a ball in there with two little rollers at 90 degrees from each other contacting the ball at all times.