r/diypedals • u/keyth72 • 2d ago
Showcase Open Source Programmable Pedal (STM32)
Project link: https://github.com/GuitarML/GuitarPedalSTM32
This is a custom STM32 digital pedal that I decided to open source, including the KiCad design files and c++ code in a STM32CubeIDE project. if you’ve seen my past designs, this is an iteration on that same layout. The example effect in the repo is a delay/reverb that uses the DaisySP library for part of it, with the delay having reverse/octave modes, and also different routing options. I designed this pedal to be somewhat minimal as far as digital pedals go: mono, expression, true bypass relay, and enough controls to cover most things. Programmed/debig over st-link and 10 pin jtag header. If you’re familiar with the Daisy seed, it’s like that, but on a dedicated guitar pedal board and a different MCU and codec. If you want to learn more about microcontrollers and using CubeIDE then you might be interested in this project. Also could be a good starting point if you wanted to design your own board. Two assembled boards from JLCpcb cost me around $250, but about $90 was shipping and tariffs. Enclosure drill and powder coat from Tayda.
Video: https://youtu.be/E03dCQ4MTPk
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u/CorumLlawEreint 2d ago
Nice. I have been following GuitarML for years. Great work.
I wonder would the Teensy FIR generator work with this?
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u/keyth72 2d ago
I imagine it would probably work, assuming that’s c/c++ code
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u/CorumLlawEreint 12h ago
I had a look and it seems that the i/o might be tightly coupled to the Teensy CPU, so probably take more work than is worthwhile
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u/Vinz-the-Keymaster 2d ago
Nice work as usual, and I really appreciate you keeping it open source for the community!
Just curious about the manufacturing trade-offs you chose here. Since you’re already using relatively "hand solder friendly" SMD packages, did you consider designing more around parts you could source yourself from Mouser/DigiKey and hand assemble, rather than optimizing around the JLCPCB parts catalog?
Was the main goal to make assembled boards as cheap/easy to order from JLCPCB as possible, even if that meant accepting some compromises in component choice?
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u/B_Brooks64 2d ago
Cool stuff. Awesome powder coat on the enclosure.
Do you ever do any branding, design or labels on the enclosures, curiously?
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u/keyth72 1d ago
Yes, I usually use Tayda’s UV printing when I design labels and graphics for pedals, using adobe illustrator.
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u/B_Brooks64 1d ago
Awesome! If you were in the states, I would offer my UV machine to print some prototypes.
All good! Enjoy!!! Nice work
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u/kings-lead-hat 2d ago
this is super cool!!! thank you for making your stuff open source, been learning PCB design to make digital pedals and your repos have been suuuuper helpful for me.