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TomK32 / PollySynth

The PollySynth is a simple synthesizer with a capacitive keyboard for input. It has 2 instances.

The box is based on Printbus' improved generic box and also uses and WarrantyVoider's rounded corners and nophead's polyhole libraries for OpenSCAD. I'm quite proud of the battery holder, the most complicated thing I created from scratch so far and it worked right away!

The box fits a 10x5cm copper plated PCB glued to the lid, a speaker, a small pcb with a battery charge controller, on/off switch and audio jack output. The brains of the whole thing is a Arduino Nano. It is powered by an 18650 battery that also prevents the copper plate from being pushed in.

Software is by Joe Marshall who happened to have created it for the very same reason I did.

The case was printed by my friends MarchGut and the assembly, design etc at my favourite place of all, DevLoL Hackerspace.


  • Keyboard cut from simple copper pcb
  • custom designed
  • 18650 battery with charging module
  • speaker

the case

Based on a design by Kevin Buehner which itself is an improvement from David Pye's design. With holders for speaker, battery and a small pcb.

Dowload it here:

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Future changes

  • Fix small issues with case
  • Wire headphone output
  • Improve input, needs some caps
  • Remove calibration from software and use a poti instead
  • Replace battery charger with an improved one
  • Find on/off swith in larger quant and a way to fix it better
  • buttons or sliders for pitch and volume