The Bit

I modified an adult sized pacifier to hold the tracking sensor. The sensor is configured to use just 3.3V, GND, SDA, and SCLK signals.

Disassembled blackberry module:

The desoldered tracking chip:

Early attempt at working out the pinout:

Initially I  was working to reverse engineer the interface for the optical trackpad/joystick/navigation buttons used on a number of blackberry phones. 

These modules are essentially tiny cameras with built in logic to determine the frame-by-frame differences of the surface being tracked, usually a fingertip, but a tongue should work as well. 

I purchased modules from two different phone models, but they turned out to use completely different internal tracking modules.