[heathkit] and a friend built this rover a couple years ago. They picked up a first generation Roomba because it had all of the features they were looking for: a good bump sensor, low profile, wheel encoders. Before removing the brains of the vacuum they put it in debug mode and figured out the control pinout. After wiring in a PIC they had rudimentary control of the device. For some higher level processing power they attached a Virgin Webplayer (defunct internet appliance). The Webplayer has a mini-pci slot so they added a WiFi card. Now they can transmit video and SSH into the device for full control.