[krkl] has been bitten by the MIDI wind controller bug. There has been a fair number of these on Hackaday but this one adds a new touch to the old trope. While this build is visibly influenced by traditional wind instruments as it uses a lot of brass and the “valves” are microswitches with levers, it deviates from the beaten path in an important way. After a first prototype that could be used to play ten notes (one per finger), [krkl] found that ten notes are not enough and gave the instrument an interface that allows one to play four full octaves, including semitones, with just six fingers. To achieve this, four fingers of the left hand are used to encode the notes of one octave as binary numbers and two fingers of the right hand select one of four octaves the same way.
Having sixteen numbers for the twelve notes of each octave left some wiggling room and so [krkl] decided to assign the whole tones to the even numbers and the next semitone to the following odd number. This leaves the player with only eight distinct finger placements to memorize, because sharp notes are played by simply adding the pinky, which plays the least significant bit.
The project page has some more details on the interpretation of the pressure data and explains the possibilities of the remaining buttons. It also provides insight into the ongoing development and a preview of the next iteration of the instrument.