Alesis Air Synth Synthesizer D-beam

via this auction
"I've controlled this Air Synth with my foot to excellent effect - though it helps to have white socks (even gloves, MJ) for best results, or lighter-bottomed shoes. You can play and control it barefoot as well. It also triggers with pieces of white paper/drumsticks/whatever. It likes to see a human hand / foot / or white surface to make the sensors work best. You can think D-Beam - it is similar to that technology, only this has 3 axis beam controls whereas D-Beams and theremins really only have 2 axis control - near and far. They don't respond to the 'left-right' axis, where this whacked machine does - often in stereo, which is really great. If I didn't have two of them, I'd be keeping it, but I am thinning the herd so take it away, eBay! I've used it nicely in reggae situations - excellent for spacey, echoed accents - and also to accompany silent films into a loop pedal. It really is sick. Fantastic device, still ahead of its time, the formant/vocal programs and weird sci-fi sounds are super useful and totally worth the price of admission, imo.

The only real interface you have (besides the XYZ sensor) is a round silver knob that selects, turns on or off, bypasses, holds and releases sounds plus an LED readout that shows you the selected program number (you can easily turn and press the knob with your foot as well). Incredible. To play the Alesis Air Synth you press the knob to turn the selected effect or pattern generator on, and then move your hand or foot through the infrared sphere to create sounds. This instrument would be great for a children's museum or music class; it is played without touching so it's not like sharing a recorder with little Billy Sickmaker."