Virtually all modern guitarists use some sort of effects pedals in their setups. The simplest kinds of pedals, such as for adding distortion, can cost less than $25. But that price rapidly increases with the complexity of the audio processing needed. Large digital pedals with multiple effects can easily cost hundreds of dollars, which puts them out of reach of anyone who doesn’t want to spend a lot of money on their gear. Thankfully there is a much more affordable option, and that’s to build your own pedal board using a Raspberry Pi.
This guide comes from Anthony Tippy, who is quick to point out that this is an advanced project that requires some experience with Raspberry Pi single-board computers (SBCs) and DIY electronics. The components required are a Raspberry Pi 3 Model B+ with a heat sink and fan, a sufficient power supply, a USB DAC, momentary stomp switches, a cheap USB keyboard, a micro SD card, a 7" touch screen, volume potentiometers, jacks, and the materials to construct an enclosure. Tippy’s build cost was about $225, but you should be able to reduce that cost if you shop around.
This project relies on two pieces of software: Guitarix and JACK, both of which are free. JACK takes care of the audio inputs and outputs through the USB DAC, and Guitarix handles the actual effects. Those effects are completely customizable, and you can setup whatever presets you like. All you have to do is install Raspbian, Guitarix, and JACK and setup them up to launch on startup. Then you can follow Tippy’s instructions to configure them to minimize latency, which should be around 5ms.
To use the momentary stomp switches to change presets, Tippy modified the PCB from a cheap USB keyboard. Alternatively, you could also use the Raspberry Pi’s GPIO pins. If you follow the same method as Tippy, you need to identify the pins that correspond to the number keys that you setup as your Guitarix effects presets. The final step is to build the enclosure. Tippy hasn’t actually done that yet, but you can get creative and design it however you like to suit your tastes.