MAKE group member Leevonk has a great Instructable on franken-modding a Furby… he writes –
“I took control of a furby’s body using a PIC16F877 microcomputer. Videos on last step.
The furby’s in-built sensors and actuators:
tongue touch sensor,
belly touch sensor,
The furby’s main (and only) motor was dead, so I added other motors.” – Link.