Bidirectional, config-driven CircuitPython firmware for Paint Audio MIDI Captain foot controllers.
Includes a GUI Config Editor!
This firmware transforms your MIDI Captain into a bidirectional MIDI controller where your host software (DAW, plugin host) can control the device's LEDs and display, not just receive button presses.
Momentary and toggle modes are currently supported. Many more issues are coming! See here for all open features and issues.
- 🔄 Bidirectional MIDI — Host can update LEDs/display state
- ⚙️ Config-driven — Customize button labels, CC numbers, colors with the GUI Config Editor.
- 🎨 Visual feedback — LEDs and LCD reflect actual host state
- 🎛️ Full input support — Footswitches, rotary encoder, expression pedals
- 🔁 Keytimes — Multi-press cycling through states (like OEM SuperMode)
- 🎸 Stage-ready — No unexpected resets, no crashes, no surprises
| Device | Status |
|---|---|
| MIDI Captain STD10 (10-switch) | ✅ Fully working |
| MIDI Captain Mini6 (6-switch) | ✅ Fully working |
| 4, 2, 1-button variations | ❔ need hardware |
- Download the latest firmware.zip and appropriate GUI Config Editor
- Connect your MIDI Captain via USB (hold Button 1 while powering on)
- Copy all files and folders from the zip to the device drive (CIRCUITPY or MIDICAPTAIN)
- On mini6, rename
config-mini6.jsontoconfig.json, overwriting the existing one. - Power off/on or unplug and replug USB to restart
The MIDI Captain MAX Config Editor is a desktop app that makes configuration easy!
Download for your platform:
- macOS:
MIDI-Captain-MAX-Config-Editor-[version].dmg - Windows:
MIDI-Captain-MAX-Config-Editor-[version].msiorMIDI-Captain-MAX-Config-Editor-[version]-setup.exe
Get the latest release from Releases
- Open the DMG and drag the app to your Applications folder
- Run the MSI installer or setup.exe
- At this time, Windows builds are unsigned. Users will see a Windows SmartScreen warning.
- To continue installation, click "More Info" --> "Run Anyway".
- Signing certificates will be obtained in the near future.
- Launch the app and connect your MIDI Captain
- Edit button labels, CC numbers, and colors using the visual editor
- Save directly to the device.
- Power cycle the device to load the new settings.
- 🖱️ Visual editing — No JSON syntax to learn
- ✅ Real-time validation — Catch errors before saving
- 🎨 Color picker — Visual color selection
- 🔍 Device detection — Automatically detects connected MIDI Captain
You can also edit config.json directly on the device:
{
"buttons": [
{"label": "DELAY", "cc": 20, "color": [0, 0, 255]},
{"label": "REVERB", "cc": 21, "color": [0, 255, 0]},
{"label": "CHORUS", "cc": 22, "color": [255, 0, 255]},
{"label": "DRIVE", "cc": 23, "color": [255, 128, 0]},
{"label": "COMP", "cc": 24, "color": [0, 255, 255]},
{"label": "MOD", "cc": 25, "color": [255, 255, 0]},
{"label": "LOOP", "cc": 26, "color": [255, 0, 0]},
{"label": "TUNER", "cc": 27, "color": [255, 255, 255]},
{"label": "BANK-", "cc": 28, "color": [128, 128, 128]},
{"label": "BANK+", "cc": 29, "color": [128, 128, 128]}
]
}| Field | Description | Default |
|---|---|---|
label |
Text shown on LCD (max ~6 chars) | |
cc |
MIDI CC number sent on press (0-127) | |
color |
RGB color for LED when ON [R, G, B] |
|
off_mode |
LED is off or dim when in OFF state |
off |
mode |
toggle or momentary button behavior |
toggle |
keytimes |
Number of states to cycle through (1-99) | 1 |
states |
Array of per-state configs (for keytimes > 1) | [] |
Keytimes allows a button to cycle through multiple states on repeated presses, similar to the OEM SuperMode firmware. Each state can have different MIDI values and LED colors.
{
"label": "VERB",
"cc": 20,
"keytimes": 3,
"states": [
{"cc_on": 64, "color": "blue"}, // State 1: 50% wet
{"cc_on": 96, "color": "cyan"}, // State 2: 75% wet
{"cc_on": 127, "color": "white"} // State 3: 100% wet
]
}- First press: Sends CC20=64, LED shows blue
- Second press: Sends CC20=96, LED shows cyan
- Third press: Sends CC20=127, LED shows white
- Fourth press: Cycles back to state 1
Each state in the states array can override:
cc_on: MIDI CC value to send (0-127)cc_off: Value when turning off (optional)color: LED color for this statelabel: Display label for this state (future)
- Keytimes defaults to 1 (standard toggle/momentary behavior)
- Maximum 99 states per button
- Works with both toggle and momentary modes
- When cycling, the button always sends the
cc_onvalue for the current state
| Input | MIDI Message |
|---|---|
| Encoder wheel | CC 11 (0-127 position) |
| Encoder push | CC 14 (127=press, 0=release) |
| Footswitch 1-10 | CC 20-29 (127=ON, 0=OFF) |
| Expression 1 | CC 12 (0-127) |
| Expression 2 | CC 13 (0-127) |
Send CC to the switch on its CC Number with value 0 or 127 to set button state:
CC 20, value 127→ Button 1 turns ON (LED lights up)CC 20, value 0→ Button 1 turns OFF (LED off/dim)
- Gig Performer / MainStage — Sync button states with plugin bypass
- Ableton Live — Control track mutes/solos with visual feedback
- Guitar Rig / Helix Native — Effect on/off with LED confirmation
- Any MIDI-capable host — Generic CC control with bidirectional sync
| Path | Purpose |
|---|---|
firmware/dev/ |
Active firmware (copy to device) |
config-editor/ |
Desktop config editor app (Tauri + Svelte) |
firmware/original_helmut/ |
Helmut Keller's original code (reference) |
docs/ |
Hardware specs, design docs |
tools/ |
Helper scripts |
Copyright © 2026 Maximilian Cascone. All rights reserved.
You may use this firmware freely for personal or commercial performances. Redistribution of modified versions requires permission. See LICENSE for details.
This project builds on work by Helmut Keller (hfrk.de), whose original firmware demonstrated bidirectional MIDI on the MIDI Captain. His code is preserved in firmware/original_helmut/ as a reference.
Open an issue or check AGENTS.md for developer documentation.
