From: Robin Hollands Subject: Re: TECH: homebrewing a motion capture system Date: Tue, 30 Apr 1996 16:33:27 +0100 Message-ID: <318632C7.34D@shef.ac.uk> Organization: Automatic Control & Systems Engineering, University of Sheffield > I'm wanting to know if it is feasible to use a combination of speakers > and microphones to rig up a very cheap motion capture system. > > The theory would be to position speakers in corners of the room, > attach mics to relevant body parts and be able to track location of > mics from analysis of the waveforms they hear. You'd have to be very careful to have speakers and mics which produced a consistant output and input characteristics. More importantly, the type of waveform received would be significently altered by the environment. Different rooms would absorb or reflect sound differently, and your position in the room would affect the very sound your trying to analyse. Even the clothes you wear into the room could have an effect on the sound. An that's all assuming that sound interference from you moving around and sound leeching in from outside doesn't screw your system up. You're probably better looking at ultrasonic timed flight systems. The ultrasonic transducers are fairly cheap, and may even work out cheaper than the audio system you were proposing. There's still problems with interference, and sensor lag, but with a little ingenuity you can rig up a room sized system that you still be affordbale. Cheers, Robin Robin Hollands