Migrated this thread from the "MIDI Setup" Section. I will continue to update this as things progressThe Project:The goal is to create a self-contained loop pedal, running Sooperlooper on a Raspbery Pi 3 Model B+. The goal is to make a pedal which requires no laptop or screen, where all controls are triggered by a stomp switches, and all settings are communicated by LED's. It heavily draws upon the original Gibson/Oberheim Echoplex Digital Pro design, but seeks to implement Sooperlooper's additional features, and introduce other ideas for a next gen loop pedal. My hopes are to provide full instructions for anyone to build one theirselves for less than $150, after I have finished the prototype.
The Design

- sooperlooperpi1.png (41.48 KiB) Viewed 11768 times
Top Row: The first 8 stomp switches surrounded by LED rings represent 8 seperate loops. Each stomp switch selects one of these loops, and causes the bottom row of buttons to manipulate that loop. The LED rings surrounding each of these loops are the Neopixel 12 RGB led devices found here:
https://www.adafruit.com/product/1643. These LED rings will allow loop-specific information to be communicated, including all of the following: loop time, total loop length, which function is manipulating the current loop at a given time, and tap. More on how all these things can be communicated will be elaborated soon. The last stomp switch, labelled "OPTIONS" will force every stomp switch to change an internal setting in Sooperlooper. This will toggle between "Loop" mode and "Options" mode at each stomp.
Bottom Row: These stomp switches are the classic echoplex functions, labelled in red below, but adding the new stuff which Sooperlooper can do such as substitute / replace, reverse, and redo. We've omitted "Next Loop", because the top row does this much better. When the pedal is switched to "Options" Mode, each of these buttons will toggle the purple options listed above it. There will be 1 purple / blue LED per option, and the stomp switch will toggle in-between lighting each LED to indicate the current setting we are on. Notice that I have merged "Replace" and "Substitute" as one button. By default that stomp switch, in Loop mode will be Replace. However, this can be toggled to be "Substitute" with the options button. I have yet to map out every setting I want the pedal to control here. More on that soon.
Project Milestones:
1. Compile a custom Realtime kernel which loads the Audio Injector stereo sound card drivers, Jack, and Sooperlooper on boot...............
Done[*(need to test Sooperlooper, only nominally running right now. Could also minimize the time it takes to boot with systemd optimizations, but stalling this project until the end )]
2. Wire Buttons, LED's, and other interface items into Raspberry Pi's GPIO pins, and control / recieve from Python...................
Done3. Write an OSC server in Python which bridges the gap between hardware interface and Sooperlooper........................
Done enough, will go back and refine after pedal build Updated 12/14/20184. Drill the Pedal Enclosure and install all Electronics......................
In Progress Updated 12/14/20185. Build a Guitar Preamp to feed into Audio Injector's inputs...................
In ProgressUpdated 12/14/2018: I found an inexpensive guitar preamp and mixer sold by FlatMax, the same Australian guy that created the Audio Injector sound card I am using. So no more need to build a custom guitar preamp circuit6. Share full directions and RPi iso images with the world!.....................
Not there yet