The detail that caught me off guard first: the crank can be spun in either direction. The Teensy only reads how fast it turns, not which way, so clockwise or anticlockwise both work. That speed drives the cutoff of a single master filter everything runs through, and to my ears that is a wonderfully mechanical take on expression.
Under the hood it is all one Teensy 3.2, handling every synthesis and control job. Twelve touch plates stand in for strings, nine momentary and three latching. An optical encoder rated at 1000 pulses per revolution sits beneath the crank arm, and the whole instrument lives on a curved wooden faceplate over a black base, with knobs, switches and the lever arranged around the pads.
Plenty stands out in the layout. The dozen circular pads carry crosshair patterns, and the gold knobs above them act as tuners split between low and high ranges. A second row above the encoder covers filter resonance, master volume, and attack and release times for the touch envelopes. The two toggles call up a tuning mode that ignores crank input and reshapes the waveforms of the strings. Range runs from roughly E0 up to F6. Only three voices act as drones at present, though the code apparently allows all twelve.
There is one interesting trade-off: the maker first tried tying rotation speed to volume, then judged the filter mapping far more expressive, and quantizing pitch never fit the vision. The 1000ppr resolution might also prove too much for a slower microcontroller. Next on the list is a eurorack version with gate and velocity outputs, pending another case. My one open question is whether those pads are small custom PCBs, and whether they sense capacitively or resistively.
Project by crushingdepths. Watch it on their YouTube channel: