The VP of Robodyssey Systems, Brian Patton, and I got together one night to have a little sumo wrestling competition. Don't get me wrong; he and I certainly didn't don our Mawashi and wrestle each other! Rather, we programmed our robots to do the dirty work. The arena was simply a piece of white poster board (shiny side up), the edge of which was lined with black duct tape. If a robot was pushed (or wandered) out of the arena, it was the declared the loser of that match. (One of the robot's wheels must fully extend past the edge of the duct tape to be "out" of the arena.) We each started with a basic Mouse robot, which is manufactured by Robodyssey. Each robot was equipped with two downward-looking IR proximity sensors that continually looked for the black edge of the arena. If the IR proximity sensor detected the black tape, it would turn to avoid it. Each robot was also equipped with at least one infrared range-finding sensor (by Sharp) to help locate our opponent. My robot was equipped with three sensors; Brian's had one. If the opponent was directly in front, the robot would rush forward to push the opponent out of the ring. With three sensors, my bot had a distinct advantage because it could turn to intercept its opponent. Both Brian and I realized early on that the robots had a tendency of locking up and had to be separated by hand quite often. We therefore added code to do a little "jog" maneuver every so often to free our robots from the other's grasp. (Brian's maneuver was triggered after his robot had moved forward some consecutive number of steps; mine did so after moving forward for more than five seconds. Also, my robot would sometimes get stuck in a corner. So it if made the same left-right-left motion 25 consecutive times, the robot would back up a few paces, chose a random direction, and turn a random number of degrees to escape. It worked well, I thought. The robots' brain is NetMedia's BX-24 microcontroller, which is programmed using the BasicX language. I am the author of the world's only BasicX textbook; if you are interested in learning how to program your own robot, see my website at www.basicxandrobotics.com.