An Opensource Arduino Guitar Pedal

If you’re a guitarist, or know a guitarist, you probably know just how many guitar effects there are out there — but what if you could design your own effects?

[J Rodriguez] has just released his opensource Arduino guitar pedal shield, dubbed the pedalSHIELD. He designed it as a platform to learn about digital signal processing, effects, and synthesizers — without needing an in-depth knowledge of electronics or programming. It allows you to design your own effects in C/C++, or download from his own library online. Some of the downloadable presets include an octave pedal, reverb pedals, delay pedals, and even distortion pedals!

The pedal features three programmable potentiometers, two main switches, and the foot pedal switch. The shield plugs directly into an Arduino Due, and you can find all the schematics here and the parts list here. It was completely designed in KiCad which is an open source electronics CAD design suite.

Take a listen after the break to hear the pedal in action!

25 thoughts on “An Opensource Arduino Guitar Pedal

    1. Arduinos are the greatest and worst things. They make the barrier to entry almost non existent. Anyone with an internet connection, a nearby radio shack, $30-$40 and 15 minutes can make something that blinks, talks to the PC via USB and responds to inputs. It used to take a lot more money, days for parts to come in and hours and hours of head scratching to get a LED to blink using a MCU. So the Arduino is great in this respect.

      The problem is those hours and hours of head scratching were filled with reading over datasheets, looking at forums and gaining debugging skills. This is now lost in the Arduino environment. Electronic skills are also no longer needed. Now instead of using a 555 timer, a shift register or other simple devices you just add another Arduino. I’ve seen an electric engineering senior design project that used no less than 5 Arduinos and no other ICs. The whole project could be done with one Arduino and 2-3 ICs.

        1. I was commenting on the comment about about the arduino rage. There is some good hardware design on this project. He probably chose an arduino to increase the range of ppl who could pick up this project and get it to work… because of its low barrier to entry.

      1. Not everyone is an electrical engineer that wants to spend days researching before they even get started. What’s wrong with an artist who isn’t interested in electronics using an arduino to add motion and interactivity to their project?

      2. And don’t forget that as soon as you are trying to build stuff at the limits of what an arduino can do, you still need debugging skills. The great thing today is that you can google almost any chip and find a datasheet or someone who has tried to connect it to an arduino so you don’t have to reinvent the wheel.

  1. One splash and no EFX. Unenclosed circuits.
    Delay and reverb are not the same, two examples are delay and no reverb is heard.
    Quality of EFX is questionable, what is bit depth and rate.

  2. Its a hellova drag when you download all the suposedly free stuff to find libraries missing . This one Kicad reports as 3 missing and investigation shows one is on his C: hard drive ,One is on his Google drive and who knows where the third one hides . Free is great but not if it is incomplete!

    1. However, it’s only a matter of impedance adaptation attacking directly ADCs and the same for DACs.

      Nothing that could not be redrawn easily.

      Anyway great project but 16 bits (instead of 12) and a Cortex-M4 (instead of 3) would certainly be better

      1. While more resolution is desirable, the Due comes with that processor and unlike the old Uno’s they are not replaceable. I’m going to use this for my senior design project, much to a previous posters rage hopefully, since I’m a computer science and mathematics major and the learning curve for all the electrical engineering is too high at the moment for me to learn DSP and EE in time to have a quality project produced. It also helps that I accidentally bought a Due and have most the the electronics laying around as well.

    2. Hi,
      Sorry for the inconvenience, Its not my aim to hide any information and nobody reported to me that missing libraries in the KiCad native files. Could you please tell me exactly what is missing to me to fix it?
      Thanks in advance!

  3. As a beginner guitarist, occasional electronics hobbyist (including a couple Arduindo projects, which I’m very happy with), and a full time programmer, I very much look forward to building one of these. Their ‘all parts included’ kit is out of stock for a few days, but as soon as they’re back in stock I’m ordering.

  4. Nice build, sounds good for experimentation, though I definitely did not like the distortion sound. Also, the “Delay” and “Reverb” effects are pretty much the same in the video, which are just regular delays, nothing like a real reverb.

    I really like how clean is his board, and how all “user interface” components are mounted directly on board. Though I did cry on the inside when he pressed the stomp switch with his foot. I’d never do that without a proper rigid enclosure.

  5. Finally someone has an interest in a guitar effects. If I were to take this to the next level I would add a 24bit A/D and D/A that could deal with up to 88kHz real time transfer rate. Then I could use this in conjunction with my analog effects and tube amp.

  6. There is a reason that professional digital effects use dedicated DSP chips. When you are using a procedural algorithm to process audio, there is invariably a delay between the input and output. Also, the amount of processing that can be done is limited given the speed of the cpu, and the sample rate. Dedicated DSP chips are made to solve these problems, but they’re more difficult to program than AVR

  7. Needs an SD card slot, for making a looper/backing track box with basic effects. Also, it needs to run off standard -9 pedalboard supplies and should allow for at least two footswitches. There’s not a lot of point in making a box that can only do things that existing budget boxes out there can already do.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.