Very interesting update from him. Apparently, the in-game packs lights and sounds are integrated into his real-world pack in real time:
The cyclotron features four blue LEDs allowing you to know which player is selected or active and the Blue Power Cell actually shows you how much power the pack has. Since the Wii-mote has in internal speaker in its ABS housing, when playing the game the pack makes all the iconic Ghostbusters SFX. And being that the Wii utilizes wireless technology, the wand is not tethered to the pack via a cord.
Found here:
http://www.gbfans.com/community/viewtopic.php?f=2&t=18931