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:

• Use Cherry style key switches for the buttons (quieter but still feel nice. Also smaller)

• Uses a custom PCB for max compactness and ease of build

• Switch out controls for a function button and encoder

• Firmware re-write

Components

DigiKey List with most parts

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