This is still in the design stage but is powered by two continuous rotation servos and a Freescale 68HC11E1 microcontroller. It has a Sharp IR rangefinder looking forward and down. It is autonomous and programed to not fall off the table.
Hey, really cool. Your robot reacts the same way the Roomba do. The Roomba has some infrared detectors in order to be able to detect stairs. When I put it on the table, the Roomba move around and never fall off the table. The difference with you is probably that the Roomba has been built and programmed by more than 100 engineers. Congratulation to you.
I will try to find some pictures for one of my projects and post it here.
See you later.