Mondo Technology has hacked a Furby in a different way. They scrapped all of the existing controllers and started from scratch.

“The mechanism of the Furby itself was designed around micro- controllers. It has one motor that runs the eyes, mouth, and ears in sequence. Two sensors are provided from the motor servo system: one counts off about 200 pulses for the entire sequence, the other is an ‘index’ pulse that lets you find the start/end of the sequence.”