Barbot was first a photropic design but evolved into a whisker driven unit. Barbot uses a PIC16C84 brain programed through a PicBasic Pro compiler. For motion the Barbot uses two hacked servos with RC airplane tires. The whisker sensors ride on pingpong balls attached to pieces of welding wire that pivot on a shaft. When the ping pong balls drop (edge of the bar) or raise (the bar counter lip) the ir beam is broken and the PIC turns the Barbot the other direction. The ir sensors are from an old mouse. Email: awilson@pacifier.com