Chris, Thanks for pointing out that 5-DOF limitation of sensing with a single 3-axis accelerometer, and also thanks for identifying that cool accelerometer/gyro chip that will be available soon. I had avoided considering gyro chips as the existing ones are much more expensive than today's accelerometer chips, but things are changing. As you can tell I'm just experimenting and imagineering a bit, and I haven't really thought this out to the level that a grad student or professor working in the field would. Mostly I'm just amazed at this sensor technology "revolution" that we seem to be enjoying presently. There are so many things that were talked about decades ago that are becoming realities today; I continue to be impressed with our society's technological progress. I guess the potential of HID's is old news to you and other more experienced ChucKists in general, especially since HID's appear to have been a ChucK feature for some time, but it's new to me and I'm excited about what I hope to do with them. Cheers. Les (Inventor)