forge

a little workshop of custom firmware for CHOMPI
some of it is magic. most of it is just really fun to play.

by DeeCee, built with Claude

_{Forge is independent community firmware, not affiliated with or endorsed by CHOMPI Club. CHOMPI is a trademark of CHOMPI Club. The code is MIT; the Choowi name and artwork are Forge's own. See TRADEMARKS.md.}

so what's forge?

Forge is where new firmware for CHOMPI gets hammered out. It's a family: every firmware that comes out of the workshop gets its own name and its own mascot, and they all live here, on the Forge tree.

The house rules (names, mascots, tools, colours) are in FORGE_FAMILY.md.

meet Choowi

Choowi is a square with spiral eyes, a chewy grin, a crooked wizard hat and a hammer that throws sparks. He turned CHOMPI into an instrument that does a surprising amount of the work for you:

• it wakes up singing. switch it on and your last sound comes back with a little chime.
• one key, a whole chord. turn on harmony and every key plays a chord in your key. the keys even light up in the chord's colour, so you can see what's happy and what's moody.
• an arp and a bass player that follow along on CHOMPI's clock (or your DAW's).
• out of ideas? hold two knobs and Choowi forges you a brand-new sound. hold two others and the sound you have drifts a little. record anything, then roll, and it becomes an instrument.
• leave it alone for a couple of minutes and it starts dreaming quietly in your key.
• design sounds right on the panel (the synth page), or describe one to any chatbot on Choowi's forge and hear it on CHOMPI straight away.
• harmony keeps a few secrets. we won't spoil them. poke around.
• its own sounds: 14 instruments and 14 drums in bank purple, free.
• everything TAPE does stays. the sampler, recording, the looper and TAPE's menu all work the way your hands already know.

New here? Start with the guide: "how do I save a sound", "how do I play chords" and friends, step by step. The whole tour, with pictures: the illustrated manual (open it in a browser), and every detail in the user manual.

Choowi's toolbox

Every Choowi release is a magic tool he forges, in the next colour of CHOMPI's panel lights.

	release	tool	what it brought
	0.16	Colour Lantern	every menu page and setting shows its colour, so you never get lost
	0.17	Wake-up Bell (and a lucky die)	the wake-up chime, surprise me, mutate
	0.17.1	Sweep Brush	the filter knob actually sweeps now
	0.18	Dream Bellows	dream mode, chomp to instrument, sparkles and ripples
	0.19	Tinker Wrench	the synth page: build a sound on the panel
	0.19.1	Thingamabob	the DJ filter never goes silent
	0.19.2	Whatzit	a few hidden surprises, the forge site, bank purple sounds

Everything before 0.16 (the synth, the TAPE sampler and looper, harmony, the arp, the event recorder, presets, the sound workshop) is Choowi's foundation. The full story is in the changelog.

put it on your CHOMPI

No apps, no accounts. Just the SD card.

1. Download choowi-0.19.2-rc2-card.zip (release candidate): the firmware, Choowi's sounds and the illustrated manual.
2. Charge CHOMPI until the battery light is green or white (hold SW6 for 2 seconds).
3. Back up the SD card (copy everything to your computer), then delete its sample files (jammi_*.wav, cubbi_*.wav) and every file whose name has .bin in it (CHOMPI installs the first one it finds).
4. Copy everything from the zip to the card's top folder, card back in, switch on.
5. Rainbow lights while it installs, then Choowi says hi. Done. (The zip's README-FIRST has the same steps.)

Updates: drop the new FORGE.bin on the card (replacing the old one) and switch on. Tinkerers on Windows can also update over USB with Forge Bridge (manual, section 2).

Want stock TAPE back? Put your card backup back on the card and switch on. Nothing in Forge touches the bootloader.

how real is it?

Honest answer: a lot of it has been checked on a real CHOMPI, some of it is waiting for a pair of ears.

• checked on hardware: the panel, knobs and lights; the synth, sampler, recording and looper; harmony chords, the arp, bass and latch; the event recorder; page and chord colours; the wake-up chime, surprise me and mutate; a stress test (CPU peaks around 67 %, a 5,600-messages-a-second MIDI flood with nothing dropped, 40/40 preset save and load).
• checked by hand on 0.19.2: the synth page, page and setting colours, harmony, saving and recalling a sound, sample start / end; the owner tried most of the rest.
• in the release candidate, being checked now: the TAPE functions' final run, harmony's hidden modes, dream mode unplugged, the forge page with a real CHOMPI.
• known issues: on some power banks CHOMPI stops charging while it's switched on (charge it switched off); the battery colour on SW6 is a voltage band (green fine, yellow getting low, red nearly empty), only white means full.
• still up to you: how it sounds, how it feels, how fun the magic is.

Every check and result is written down in TEST_RESULTS.md.

make sounds with any chatbot

Open Choowi's forge in Chrome or Edge, plug in CHOMPI and press Connect. Describe a sound, copy the prompt into any chatbot (ChatGPT, Claude, Gemini…), paste its reply back: CHOMPI plays it. Tweak it live, play it from the on-screen keys, Save to CHOMPI (a preset slot) or Save JSON. No install, no API key, no account. No CHOMPI handy? "make sounds anyway" and send them later.

Choowi's own sounds are bank purple (14 instruments, 14 drums, free) in the card zip, or in firmware/chompi-forge/samples/choowi-pack.

for tinkerers

make -C firmware/chompi-forge test         # the native and Python tests
make -C firmware/chompi-forge firmware     # FORGE.bin (GNU Arm Embedded 10.3-2021.10)

the original CHOMPI release

Everything below is CHOMPI Club's own README for the release Forge builds on, kept as they wrote it.

CHOMPI is a quirky chromatic sampler and tape-music instrument by CHOMPI Club.

This repo contains all of the production files, both hardware and firmware, that make up the CHOMPI Sampler.

What's here

Each folder contains its own README, so check those out for more details.

What's not here

The panel artwork. The graphic set and CHOMPI logos have all been removed for copyright purposes. If you choose to create your own hardware, we ask that you name it something else to avoid trademark infringement.

Support Guidelines

This is a discontinuation open-source release. As such, this repo is intended to be a permanent source for files and documentation, and will likely not be receiving updates in the future. If you wish to customize your own project, we recommend cloning this repo into your own GitHub.

Community

Even though this version of CHOMPI is now discontinued, the CLUB is expanding. If you want to discuss this project, share your creations, see what other users have made on their CHOMPI, feel free to check out the CHOMPI Open Source channel on the Chase Bliss Discord.

License

Everything here is MIT — see LICENSE. THIRD_PARTY.md lists the work this builds on and the notices that come with it. The CHOMPI name, logo and artwork are not covered by the license — see TRADEMARKS.md.

HAPPY CHOMPIN'