See inside your looper. LooperCat is a companion app for the BOSS RC-5: browse all 99 memory slots, listen to loops, rename, trim, re-tempo, upload and download WAVs — while the app drives the pedal's STORAGE mode for you.
Part of the Felitronics family by Darwin's Cat. Built on the RC-5 file-format knowledge of rc5cat.
Beta. Everything below is verified against real hardware, and every write runs behind automatic backups — but treat v0.x like the beta it is.
- Connect / Disconnect. One button puts the pedal into STORAGE mode and mounts it; one button ejects politely and returns it to the looper screen — over USB-MIDI SysEx, with zero trips through the pedal's SETUP menu.
- Browse. All 99 slots in one table: name, duration, bars, tempo, the behaviour lamps you choose to show, WAV file. Live refresh as the pedal comes and goes.
- Listen. Double-click a slot to play it — waveform, seeking, output device picker. No copying files around just to hear what's in slot 37.
- Set a slot up. A Properties tab per slot: its name, its true tempo with the bar count that follows, One Shot, and Play Count-In — one measure of count before the loop, without walking the pedal's menus. Disconnect and the pedal has it.
- Edit audio. Trim with a gapless preview of the cut, clear a slot, drag one slot onto another to swap them.
- Move audio. Push a WAV into an empty slot or replace an occupied one (converted to the pedal's canonical float32 format; the old loop goes to the app's trash first), pull any loop out as a standard WAV.
- Stay safe. Config backups before every mutation, write-generation counters matching the pedal's own discipline, junk-file hygiene (macOS AppleDouble droppings), a doctor that checks card consistency — and honest ghost detection with automatic cleanup when the pedal leaves without saying goodbye.
The whole map, feature by feature: docs/guide.md.
When you import a WAV through the card, the RC-5 assumes the loop is a power-of-two number of measures — 16, 32, 64… — so any other loop gets a wrong tempo, and the onboard rhythm drifts against the actual music. LooperCat makes the arithmetic visible — the Bars column — and editable: set the true tempo and bars on any slot, and the pedal's rhythm finally agrees with the music. Automatic tempo-true upload (the right numbers written the moment a WAV lands) is next on the roadmap (#26, #28).
The RC-5 talks to a computer by exporting its SD card as a USB drive — but only after a manual trip through SETUP → USB → STORAGE on the pedal, every single time. It turns out that mode can be flipped remotely, and LooperCat speaks the protocol: Connect sends the SysEx, waits for the medium, and mounts the volume; Disconnect unmounts and sends the pedal back to looping. The protocol notes live in docs/midi-protocol.
macOS first: grab the DMG from Releases, drag LooperCat to Applications, plug the RC-5 in over USB, press Connect. Universal binary (Apple silicon + Intel). A Windows build is planned once the macOS release settles.
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --target LooperCat
ctest --test-dir buildJUCE and felitronics-appkit are fetched automatically; the app lands in
build/LooperCat_artefacts/.
BOSS RC-5, developed and verified against a single real unit on firmware
Ver 1.10 build 0050 (the current official release). The format layer
is pinned by conformance tests against values captured from live hardware —
the golden fixtures checked in at fixtures/golden.json, shared lineage with
rc5cat. Other RC-series pedals
(RC-500, RC-505…) are not supported: their cards look alike — alike
enough to seem to work — but speak a different data dialect, so LooperCat
checks who it is talking to and refuses a foreign card with an honest message
instead of guessing (#35).
AGPL-3.0. LooperCat is built with JUCE under GPLv3; GPLv3 code may be conveyed inside an AGPLv3 work (GPLv3 §13), so the combination is distribution-safe.
LooperCat is an independent project: not affiliated with, endorsed, or sponsored by any hardware manufacturer; all trademarks belong to their respective owners. "BOSS RC-5" is used nominatively to state compatibility.
Bugs and wishes → issues; everything else → band@darwinscat.com.