Just a sneak preview of a Mappydot piano that is being made up for Makerfaire Adelaide (and its own build guide for you to build one too). It is run by 8 MappyDots (on the dev breakout boards) and a Teensy 3.2 while using the awesome Teensy audio libraries to do all the work. The Mappyano has an integrated amplifier/speaker and power supply as well, so you just have to drive it with 5-12V and out comes all the noise you need to drive your housemates/spouse/fish crazy. There's 8 keys, but there will be some modifier buttons as well to change the note's output. There will also be USB out to allow for use as a midi device.
The notes have a striking distance threshold and an output velocity that controls the Attack-Decay-Sustain-Release of the note. So depending on how you hit the air, the notes change their tone.
Once everything is hooked up, there's some extra sections to restrict the viewing angle of each of the MappyDots which are held in with some small screws. This prevents excessive measurement overlap between each sensor: