About this 3D model

This is just the same robot as http://www.thingiverse.com/thing:18264 But I've created a new part: spacers. Their objective is to support the Arduino board, allowing to place a 9V battery below it. Its advantage is that the battery is just above the wheels, so the grip is slightly increased :) The Arduino code which makes it able to navigate inside a corridor is also attached. Video of NS-1 working here: http://www.youtube.com/watch?v=xKkJGlzjeCM