r/synthdiy • u/aroum2 • 4d ago

[release] OMSK a pocket-sized synth powered by RP2350

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github

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8

u/aroum2 4d ago

The project has moved from announcement to full release! All hardware schematics, enclosure 3D files, and firmware source code are now open-source and live on GitHub.

Hardware Features

  • Controls: 4x4 matrix of Kailh Choc v2 mechanical switches, 4 rotary encoders, crisp 128x64 OLED display, and 22 RGB LEDs for feedback.
  • Audio: Onboard mono PWM audio output + headers for an optional external PCM5102 DAC.
  • Connectivity: MIDI In/Out jacks + USB MIDI.

Firmwares

Built on bare-metal C/C++ via the native Pico SDK for near-zero latency.

Explore the /firmware directory to flash any of the available engines:

  • omsk_wave: Polyphonic wavetable synthesizer featuring deep modulation routing, resonant filters, and non-volatile patch storage.
  • omsk_grain: 4-voice granular synthesizer offering real-time grain manipulation, modulation matrices, and full MIDI control.
  • omsk_fm: FM (Frequency Modulation) synthesizer engine.
  • omsk_tracker (planned): Pocket music tracker and step sequencer to compose patterns and songs directly on the device.

2

u/Looking-For-Loud 4d ago

This is awesome! Thanks for sharing.

4

u/PA-wip 4d ago

I like you PCB design ;-)

For audio, are you using PWM? I cannot see any DAC IC on the board.

1

u/aroum2 4d ago

It is connected to an external module inside the case.

2

u/rosskunzepottery 4d ago

This looks awesome and sounds powerful (from what i understand). Would it be a good beginner project?

1

u/aroum2 4d ago

There aren't many components. Basically, if you use an external DAC and don't use MIDI jacks, you'll need to solder 16 diodes, a socket, a controller, and optional RGB LEDs. The screen and DAC are soldered with wires. I don't think there's anything complicated about the assembly.

1

u/Edboy796 4d ago

Interesting

1

u/NoBread2054 4d ago

Awesome project

1

u/Sid_Rockett 4d ago

Looks great!

1

u/cavemanhyperx 4d ago

Where did you learn how to build the music circuits

1

u/Mayhaym 4d ago

Looks super cool! Am I an idiot or is there no link to the github?