ESP32 Guitar Shield

An Arduino-programmable guitar effects pedal

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The ESP32 is capable and Arduino environment lowers the entry level of digital signal processing.
Goal of this project is to have a complete Guitar-Shield for the ESP32 Devkit-C. It will feature a nice FET guitar preamp and a high quality ADC/DAC. The shield should be small enough to fit into a standard Hammond 1590BB case.
You'll find an audio library for the ESP32 on GitHub which handles all the low level stuff and at least some example signal processing blocks.

Working on a client's project I found the ESP32 a pretty capable chip. I was blown away by the processing power and did some audio experiments with it. The Teensy audio shield didn't fit well and was not satisfying in terms of audio quality so I searched for other codecs out there. Well, this got a little bit out of control and I started this project....

KiCad Library with some special components I use in the GuitarShield project

Zip Archive - 1.73 MB - 04/15/2020 at 21:27


KiCad schematics and project files

Zip Archive - 15.63 kB - 04/15/2020 at 21:24


  • 1 × AKM AK4556 High quality stereo audio codec
  • 1 × ESP32-DevKit-C The official Espressif ESP32 Devkit
  • 1 × 2N5457 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs

  • KiCad Schematics

    GaryGru04/15/2020 at 21:30 0 comments

    I've just uploaded the KiCad schematics for reference. It's still a draft, no complete prototype built yet. 

  • yummyDSP Arduino audio lib

    GaryGru06/05/2019 at 08:58 0 comments

    I've uploaded the library I'm working on to GitHub. I also added a hackaday project for this. You're welcome to contribute, still a lot to do!

  • first simple playthrough test

    GaryGru05/21/2019 at 19:51 0 comments

    First messy prototype is making sound! Codec module (see my other project, Yummy ADDA Cookie) seems to work nice, no dropouts. Sounds good but want to measure the noise level soon.

  • Codec Module

    GaryGru05/07/2019 at 07:08 0 comments

    I'm currently working on the codec board, which holds all the fine pitch stuff. The PCB just arrived. See my ADDA Cookie project for more details...

  • Next steps

    GaryGru04/01/2019 at 07:53 0 comments

    I'm thinking of modularising the project. Splitting it into a small FET Preamp module, an AD/DA module and an IO-Board which holds everything. I really like the small castellated holes-style PCBs like the ESP32 module. Have to check how to do that in KICAD...

  • Prototype phase

    GaryGru03/27/2019 at 09:10 0 comments

    This project is in a pretty early stage. I'm working on the prototype board. Lot's of design decisions are still to do. Any input or discussion is welcome.

    Challenges are: 

    • The small form factor while having huge components like all the jacks and the stomp switch
    • Signal to noise ratio must be high as guitars get highly amplified in later stages
    • Should be not too hard to build
    • Should be not too expensive

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GaryGru wrote 06/27/2019 at 11:40 point

Hi Hasan, yeah this would be a really cheap alternative. Probably a little noisier but having everything onboard is pretty tempting. This module even has the 4MB of extra RAM! I should get one of these. Beside the low level stuff, your code port shouldn't be problem. 

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Hasan Murod wrote 06/23/2019 at 18:18 point

I'm interested in this project since I plan to use ESP32 for my next pedal project. I think I would use ESP32-A1S module from Ai-Thinker since it has interegated AC101 codec inside the SoC module. I hope I can port some codes of my Deepstomp multi-effect pedal platform into ESP32 version. 

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