[Bruceb]

From watching several competitions now I have to say that those of you trying to use the drivers depth perception and an arm to lower the bridge have 2 problems. 1. getting the bot at just the right distance from the opposite side of the bridge to allow your arm to lower the bridge is difficult at best.
2. developing enough torque with a motor and coordinating its lowering with your forward motion is a trick in itself.
Solution. just lower a wedge shaped arm at the front of your bot using an over center link(motor or pneumatic) and just drive up the bridge to lower it. see our bot here.

http://i1121.photobucket.com/albums/...2/100_0011.jpg