12 Step Editor for iOS

An iPhone and iPad editor for the 12 Step MIDI foot controller by Muse Kinetics (Keith McMillen Instruments). Plug the 12 Step into your phone over USB-C, edit presets, chords and the setlist, and send them to the pedal. You don't need a computer.

Status: preparing the first App Store release. Everything below works and has been tested on a real 12 Step2 (firmware 1.0.9) with an iPhone 16 Pro.

What it does

• Covers everything the desktop 12 Step Editor does to presets, the setlist and global settings, using the same files, so presets move freely between the two.
• Easier note assignment. You see the 13 keys as they sit on the pedal, each showing its chord name.
  • Tap a key to pick notes on a small piano or choose a chord: major, minor, dominant (including 7♯9 and altered), suspended, diminished and augmented.
  • Fill all keys builds a whole preset at once from a scale and key, for example "F major, 7th chords". You choose what the keys outside the scale do.
• Sends to the 12 Step over USB-C. Setlist and settings uploads are byte-for-byte identical to the desktop editor's. Settings changes take effect on the pedal as you make them, as they do on the desktop.
• Shares presets with the desktop editor on a Mac through iCloud Drive, optionally. The free 12 Step Sync Mac app (in this repo) sets that up in one click.
• Touch and hold any setting's name for an explanation, written from the official manual.
• Demo mode (Device tab) lets you try the app without a 12 Step.

Not included: firmware updates, and the pedal and CV calibration tools. Use the desktop editor for those.

Compatibility

	Supported (tested)	Expected to work
Controller	12 Step2, firmware 1.0.9	—
Device	iPhone 16 Pro, iOS 26	Any iPhone or iPad with USB-C, iOS 17 or later

The 12 Step is class-compliant USB MIDI, so the app uses Core MIDI and needs no drivers.

The original 12 Step isn't officially supported, because it hasn't been tested. The app includes the original's messages from the desktop editor, so it may well work. If you try it with an original 12 Step, please open an issue saying what worked and what didn't. Reports are very welcome.

Is it safe for my pedal?

The app only ever sends the same messages the official desktop editor sends: read-only queries, setlist uploads and settings uploads. A setlist upload replaces the presets on the 12 Step, exactly as the desktop's "Send Setlist" does. The app asks before doing it. It never sends firmware or bootloader commands, and a safety check in code refuses anything that isn't on that list.

Sharing presets with the desktop editor (optional)

1. On your Mac, build and open 12 Step Sync: Tools/sync-setup/build-app.sh makes Tools/sync-setup/dist/12 Step Sync.app. Click Turn On iCloud Sync. It:

   • backs up the desktop editor's presets;
   • copies them to iCloud Drive/12 Step Editor;
   • points the desktop editor at that folder.

   It never modifies the desktop editor app itself, and Turn Off Sync undoes it.

2. In the iOS app, tap Set Up Sync on the Presets tab (or Settings › Sync with Your Mac…), then pick iCloud Drive › 12 Step Editor.

Quit the desktop editor while editing on the phone, because it doesn't notice outside changes. If the desktop editor ever says a file is missing, choose Exit Application, never Factory Default.

Building

Requirements: Xcode 16 or later. The app targets iOS 17.

• App: open TwelveStepEditor.xcodeproj, choose your team under Signing & Capabilities, pick a device, then press ⌘R. Without a 12 Step, turn on Demo mode on the Device tab.
• Tests: cd TwelveStepKit && swift test (protocol, file format and editing logic, including golden upload bytes from the official editor).
• 12 Step Sync (Mac): cd Tools/sync-setup && swift test && ./build-app.sh

TwelveStepEditor/            SwiftUI app (Presets, Setlist, Settings, Device)
TwelveStepKit/               Swift package with no UI: MIDI transport, 12 Step protocol, preset files
Tools/sync-setup/            12 Step Sync, the Mac app for iCloud sharing
Tools/golden-harness/        builds the official editor's formatter to produce reference upload bytes
Tools/mac-sync/              older Terminal-script version of 12 Step Sync

Acknowledgements

• Muse Kinetics publishes the source of the official 12 Step Editor under MPL-2.0. This app's protocol and upload code is translated from it, and the factory presets come from it.
• The 12 Step manual is the source for the in-app help.

Licence

Source-available: free for noncommercial use, and commercial use needs permission.

• Most of the project: PolyForm Noncommercial 1.0.0.
• Stays MPL-2.0: the files derived from the official editor.
  • Protocol/KMIFraming.swift
  • Protocol/PresetImageFormatter.swift
  • Resources/FactoryPresets/
  • Tools/golden-harness/

Each source file's header says which licence applies. See LICENSE.md for details, including the terms for contributions.

The app collects no data; see PRIVACY.md.

12 Step is a trademark of Muse Kinetics (Keith McMillen Instruments), used with permission. This is an independent project, not made by Muse Kinetics.