Accelerometers: My Favorite Trick of 2008

Most of us have held an accelerometer in the palm of our hand quite recently. Can’t figure out when? Still trying? iPhone. The iPhone and iPod Touch both use accelerometers to sense how they are being oriented. Need another example? How about the ever fun Nintendo Wii? The Nintendo Wii uses a 3-Axis accelerometer (in each remote) to sense how you are holding the controller.

Optical Marker Based Motion CaptureNow an overpriced iPod or an entertainment console are not enough for me to call these little devices my favorite trick of ’08. Thanks to the auto industry, the size, and cost of accelerometers has gone down, while the sensitivity and accuracy has gone up.

I recently got to wear a 3D Performance Capture Suit; this technology is used in video games and cinema quite extensively. Most of the systems out there are based on infra-red cameras and about 20 – 60 little white balls on a black body suit. The dozen or more cameras see the points of reflected infra-red light and some triangulation will give you a swirling point cloud of data that you can then extract the performance from. The suit I wore was different though; it was wireless, marker-less, required no cameras, and was worn underneath my jeans and t-shirt. It was based largely on accelerometers.

Actor Standing in Moven Suit. Notice the Orange Modules on his feet.The suit I am raving about is a spandex (ouch!) suit that has modules the size of camcorder batteries in pockets on each limb. One on your forearm, one on your upper arm, a few on your shoulder blades, etc. In addition, a module is strapped onto your head (using a standard headband with a pocket sewn onto the back of it) and there are modules on your hands and feet. Seriously, once you get over the crotch hugging spandex, you can barely even feel it on you.

I was one of two lucky students who got to wear the Moven inertial based motion capture suit. We filmed the whole thing, and eventually we will put together a nice (definitely funny) video of all the things my schoolmates made me act out in this suit.

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