I'm getting some parts & info together to make a Segway-style balancing bot. Here's a nice balance bot webpage with many interesting links to other sources, including Trevor Blackwell (of AnyBots) and his homemade Segway, near the bottom: http://www.tedlarson.com/robots/balancingbot.htm#flexo
Another guy used a Ping sensor (he goes on in some detail about how well it works) with an Arduino controller: http://www.societyofrobots.com/membe...rials/node/185 (more good links)
And another: http://geology.heroy.smu.edu/~dpa-www/robo/nbot/
Anyone with any balance bot success is very welcome to chime in here!