I assembled a poly555 from oskitone.com :D
It's an analog polyphonic square wave synthesizer. This means no code involved, it can produce multiple note at once and it make kinda harsh sound.
The case is 3D printed plus a piece of plexiglas and half a dozen nuts and bolts. The plexiglas expose the twenty 555 timer circuits and their led showing which ones are playing, What's not visible is the voltage regulator for the 9v battery and the amplifier for the speaker under the grid,
@gkrnours Glad I learned about this. How long did you work on soldering & assembling it, and how finicky was it to tune?
@ozdreaming guide advertised 5+ hours, I spend a day and a half with some media in the background, mostly soldering. Assembly is maybe 10 minutes. All the keys are one big part, yellow shell is two part, top and bottom, hold together by 4 nuts and bolts. 3D printed parts were included in the kit which help.
The tuning is a bit finicky. Small movement from my hand moved the tune by ~10Hz, I went up and down a few time for each note until I hit close enough. I would say a minute or two per note.
@ozdreaming I could see a 3D printed tool with some gear reduction to make one turn by hand resulting in 1/36 of turn in the potentiometer. That or maybe using potentiometer with less range and have different circuit use different resistor. The current kit have 20 identical square wave generator
@ozdreaming I'm curious about the scout, it's monophonic and use a microcontroller instead of analog circuit, so tuning is easier and I wonder if it could output something other than a square wave