We have Keepon control!
Yay! Thanks to mAngO on the comment thread for my last keepon post, we now know that grounding out the bus during keepon's powerup allows you to act as the master to the bus! This means we can now control the motors and sound, as can be seen in the video above. I'm just controlling motors there, using the Control Program for Android to send OSC messages to a python script I wrote. The python talks to the USB serial port, and the arduino turns the commands coming over serial into I2C to go to keepon.
All the source code for this is available in completely raw, uncommented form at
http://www.github.com/qdot/keepoff
So, that's the first part finished. Now it's on to polishing things out and figuring out the rest of the parts of the hardware we don't have access to yet. I'm keeping the github issues list updated with things we have left to do.