DJBB-Midi-Loopster
The Midi Loopster is a MIDI 4x4 drum pad and midi looper based on the Raspberry Pi Pico.
Demo: https://www.youtube.com/watch?v=YDxO62Sy1Qc&lc=UgxtoEvjVZX9zsOcOUB4AaABAg
Build Video: https://youtu.be/qznFqSrzPKM
Background
I created the DJBB Arcade Button MIDI Drumpad as an experiment on how to use a Raspberry Pi Pico microcontroller as a Midi controller.
It worked pretty well but I honestly don't like the super loud arcade buttons so I never really used it. I wanted an excuse to try designing my first PCB, so I decided to go for a version two of my original design except with these changes:
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Use Cherry style key switches for the buttons (quieter but still feel nice. Also smaller)
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Uses a custom PCB for max compactness and ease of build
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Switch out controls for a function button and encoder
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Firmware re-write
Components
Also see BOM csv in this repo
1 x DJBB Midi Loopster PCB
1 x Raspberry Pi Pico or Pico W With Headers **djt depends on wifi stuff
1 x SSD1306 OLED Screen
5 x 10k Resistors
1 x 10 Ohm Resistor
1 x 33 Ohm Resistor
17 x Cherry MX Style key switches
1 x Rotary Encoder
1 x 3.5mm Audio Jack
3 x 10nF Capacitors
17 x Cherry style keycaps (technically optional... but you want em)
1 x 3D printed case (optional)
1 x 3D printed screen case (optional)
1 x 4 pin female large headers for screen (optional)
4 x m2.5 screws - for screen case (optional)
4 x m3 screws - for case (optional)
Models for printed parts here: https://www.printables.com/model/661953-djbb-midi-loopster-3d-printed-parts
Assembly
See the detailed Loopster Manual and Assembly Guide pdf in this repo for in depth assembly instructions.
In short:
- Solder the fn button and top left pad to the front of the board. You must do this first!! These are the top-leftmost buttons.
- Solder everything else (The pico, aux, and 2 resistors go on the back).
- Follow Adafruit's guide for installing CircuitPython on your Pico
Firmware Upload (use this to update as well)
- Delete everything from the Pico on your computer (should be showing up as a USB drive on your computer).
- Download and copy everything from "src" in this repo to the Pico
Usage
See the detailed Loopster Manual and Assembly Guide pdf in this repo
I also sell PCBs/Kits here if ya want: https://djbajablast.etsy.com
Changelog
Mar 24
- chord mode added!
- Updated logic to make it harder to accidentally change midi banks when setting velocity / encoder mode
- Scales fixed & more added. Now you can choose the root and the scale separately.
Nov 23
- Created new user guide + assembly manual
- Created loopster_settings.json file for easy default config
- Added performance mode config option
- Added looper feature - twist encoder CCW to remove a random loop note
- Added more scales