All the sounds you hear were played on the AirHarp with the exception of the drum tracks, which are canned samples. I could have used the AirHarp for the drums as well, but I’m no percussionist and I have trouble conceptualizing music in purely rhythmic terms. Thus I will leave the exploration of the AirHarp’s percussion capabilities to someone else.
How does it work?
The AirHarp emits a beam of ultrasound that’s undetectable to the human ear. It bounces this beam off your free hand to determine the distance between your hand and the device. This is a form of ultrasonic sonar ranging. A microcontroller continuously monitors the output of this sensor, along with the status of each pushbutton. Calculations are performed to decipher the coded chord input and compute the desired note pitches based on readings from the ultrasound. A list of active notes is maintained and used to determine which notes to turn off and when. Information on which notes to activate and deactivate is coded into a serial data format called MIDI and transmitted out of the microcontroller into either a synthesizer module or to an outboard computer through a USB cable. The synthesizer module or computer then converts these “note on/off” commands into audible sound.
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