Wollan said:
No, the PSMote. For example, the FPS section. He aimed around with one remote and it showcased every little shake in his hand instantly. Minute movement. How do they determine the aim? It looked way too precise and instant to be just accelerometers.
The ultrasonic sound and ball positioning seem enough for one x,y,z reference point but they would need a second reference point somehow.
I'm speculating since there really isn't much information available at the moment, but it seems to me that the Sony Remote is using a combination of optical mocap techniques using markers (using the LED orbs), ultrasound, biometric techniques (facial recognition, etc), and the use of orientation based sensors (accelerometers etc).
The combination of those techniques should be more then enough to get that level of accuracy. Writing with the LED orb alone is conceptually similar to those pictures where people write out words or drawing pictures using a penlight and a long-shutter speed camera.