[11douglash]

What we did is find a 4 way light switch (i believe). Basically, it was a switch that flipped polarities. Then there was another switch that triggered when the robot hit the pole.

Our minibot went up, flipped the polarity switching switch, powered down, hit the bottom, and then, due to the mechanical way the wheels were rotating, fell off, and thus broke the switch that kept it powered, and turned off.