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Polaron is a DIY digital drum machine based on the Teensy 3.6 USB Microcontroller plattform.

Main features:

  • 16 step sequencer
  • 6 instrument tracks
  • 16 patterns per track
  • load/save projects to SD card
  • 2 pots for parameter control
  • parameter locks: all instrument parameters can be recorded for each step
  • different pattern length for each instrument track
  • sync to midi-clock (usb-midi) or trigger input
  • crunchy 12bit stereo outputs
  • open source hardware/software: if you miss a feature or are annoyed by a bug... change it!

Disclaimer: This is a DIY project, features may change or not work for you. Use at your own risk.




here's some short videos:

Follow the project on Instagram:

And don't forget to check the Project WIKI for more info.


To build the software, the following tools are required:


PCB is designed using KICAD 5.1.2

Parts needed (Rev 1.4):

  • Teensy 3.6 32bit Microcontroller (with Headers)
  • 30 x WS2812b RGB LEDs (or SK6812)
  • 30 x 6x6mm Pushbuttons (ideally 4.3mm height, 100gf) (Mouser: 688-SKHHAJ)
  • 16 x 270 ohm throughhole Resistors (Mouser: 603-MF0207FTE52-270R)
  • 14 x 270 ohm SMD Resistors (1206 housing)
  • 2 x 10k SMD Resistors (1206 housing)
  • 1 x 1N4148 diode
  • 1 x 2N3904BU transistor
  • 4 x SN74HC165N Shiftregister (Mouser: 595-SN74HC165N)
  • 2 x ALPS Potentiometer (RK09K1130A8G)
  • 2 x 2.2 uF SMD Capacitor (1206 housing, Mouser: 963-TMK316BJ225KL-T)
  • 2 x Audio Jack (SJ-352X-SMT)
  • 1 x 48 Position / 2 Row IC DIP Socket (Mouser: 517-4848-6004-CP)
  • 2 x 20mm PCB Standoff with 3mm thread (Mouser: 534-24437)

Check the Wiki for Build Instructions

Known Issues:

PCB Rev 1.4

  • In some situations, when connecting the polaron to a computer via usb and connecting the polaron audio output to an audio interface that is connected to the computer (e.g via thunderbolt), a ground loop is created. This results in a very noticable noise/whine in the audio channel (which is caused by the LED PWM). Tested solution: Audio Ground Loop Noise Isolator


  • Q: Is this an easy build? A: This is an intermediate project to build. Its not very complicated, but there are some SMD parts which are not easy to get right (the LEDs). You'll need a decent soldering iron, with a rather fine tip.
  • Q: Is this a pro audio project? A: No, not exactly. The Polaron is more about a fun workflow than super hifi sound.
  • Q: Does it work with a Teensy 3.5? A: PJRC forum member drjohn reports successfully running the Polaron with a Teensy 3.5.
  • Q: Does it work with a Teensy 4.0 / 4.1? A: No, the Polaron relies on the internal DAC of the Teensy 3.6 and is not compatible with Teensy 4.0 / 4.1
  • Q: Is there a manual? A: Yes, please check the Project WIKI for build instructions and operating manual. If you still have questions / suggestions, please send me a mail.
  • Q: Does the polaron fit into a euro-rack? A: No, not really (PCB size is 15.7cm x 11.6cm). Polaron builder N.Shaver has experimented with a 3D printable eurorack case for the polaron which he shares on Thingiverse
  • Q: Can i buy a PCB? A: Sold out, but let me know if you'd be interested in buying one. Yes, i currently have PCBs at 15 USD (+ shipping from switzerland). Please contact me by email, if interested.
  • Q: Can i buy a part-kit? A: I don't sell part kits anymore, since it is very easy and efficient to order parts online, eg. from mouser. Yes, i currently have part kits (PCB + all parts, EXCLUDING the teensy itself) at 60 USD incl. untracked international shipping. Add 5 USD for tracked shipping. Please send me a mail, if interested.
  • Q: Can i buy a fully assembled Polaron? A: Not, not at the moment.
  • Q: How can i support this project? A: Spread the word, star the project on github, let your friends know, buy a PCB, build a Polaron and share a video...there are many ways. In general, knowing that this project sparks some interest is what keeps it going!


Code: MIT

Hardware: cc-by-sa-3.0

By: Thomas Zueblin (

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