View of the bot (the "H" bridges aren't finished on the picture).
The "Trick", put connection for motor wires so you can cross them, the bot will become light seeker, light avoider or crazy dancer if you plug one motor reverse !)
Bottom : the batteries are located very low which improve stability and motion. The stabilisator is a tape roller from an old "Walkman".
Note the way the gears shafts fit into the "bearings"
all the parts are made of 5mm thick Polycarbonate and glued together with cyanolite glue "super-glue"...)
Gears and engine came from "Conrad Electronic".