I’ve been working on this prototype rover robot which proved to be a worth while endeavour.
I found the motors in the Roomba to be very user friendly. The have a planetary gear and belt driven assembly inside that provides very good torque and they can be driven directly from the H-bridge that is already on the Roomba main board!
I mounted four of these on the suspension arms, two on each side. They were then connected to the mainboard at the factory plug. I did however load up the circuit with double the normal load because I was using two motors per side. It seems to handle this just fine.
The Arduino microcontroller I installed sends a PWM signal to the trigger transistor on the H-bridge of the main board which is powered by the Roomba battery pack. Mounted to the front of the chassis is a Parallax PING sensor which tells the controller when there is an obstacle.
Here’s a video of the prototype in action
http://www.youtube.com/watch?v=xrPBWtjbHKs
I’m currently working on a more final design to take to the 2010 Maker Faire in San Mateo in May. I’ll be building a new chassis and suspension assembly out of aluminum and making use of one of the IR edge sensors from the Roomba. I’m working on a really neat wheel driven by the stock motors… stay tuned. 