From building your own analog effects pedal to processing audio through micro controllers, a lot of musicians love building their own boxes of sound modification. In his entry for the 2019 Hackaday Prize, [Craig Hissett] has a project to build an all-in-one multi-effects stomp box.
At the center of the box is a Raspberry Pi with an AudioInjector stereo sound card. The card takes care of stereo in and out, and passing the signal to the Pi. The software is Modep, an open source audio processor that allows the setup of a chain of digital effects plugins to be run on the Pi. After finding some foot switches, [Craig] connected them to an Arduino Pro Micro which he set up as a MIDI device that sends MIDI messages to the Modep software running on the Pi.
There are still a few steps to go, but [Craig] has the basic layout covered. Next up is wiring it up and building a proper case for it, as well as working on latency. A few years ago, another multi-effects stomp box was featured in the Hackaday Prize, and last year, this multi-effects controller was featured.
There are tons of multi fx on the market. What I have not seen but someone must have done by now is to create a fidget that replaces the hex nut that holds the pot in place in an extant effect, and joins it up with a small hobby servo or stepper under computer control. Let you use your electronically unmodified classic effects but have computer controlled presets.
A much better way to do what you’re talking about is to replace the pot with a digital pot controlled by an arduino.
Yuck, with a huge capitol Y. The main idea of what I would want to do would be to NOT do anything to the classic effect. My way it just turns the pot like you normally would, and if you used a stepper you could eve have the pot on the back end of it so you still have full manual control. No screwing with the guts at all. Your way means screwing with the guts, tangling digital stuff and very low level analog stuff together, and messing with the innards of a classic device. Not that it probably could not be undone, but it would take some doing, My way the device remains untouched save the hex nut that holds the pot in is replaced.