This is a quick video describing my robot Spyder's orientation sensing. There is a metal and ceramic encapsulated mercury (Hg) switch near the rear of the robot. This ties into the motor inhibit/enable circuitry in the conditioning board. It shuts off drive to the H-bridges, saving power and keeping the robot from squirming when picked up and handled.
For more info, please visit and Enter the page below and click the "Robotics" link in the navigation bar.
http://richfiles.solarbotics.net
