music that matches how your body feels
A mobile app that plays music based on the vibes of your fitness data. Originally built for the iKKO MindOne, it runs on any Android phone using data from your Oura Ring. It reads your biometrics, understands the feel of your own music library, and plays what fits — with a full-screen, nostalgic Winamp visualizer.
📝 Read about how it was built and the lessons learned: I built a mobile app with Claude Code in 4 days
 Home — your state at a glance |
 Mood color — shifts with your energy |
 Paused — dozes when the music stops |
 Mood — override the vibe |
 Why this track — the read behind the pick |
 History — rate past picks |
 Visualizer — full-screen & audio-reactive |
||
Runs on any Android phone, not just the MindOne — here on a Jelly Max:
 First run — add music, connect Oura |
 Visualizer — same experience, different device |
Most "mood" players use a music streaming service and react to a single number like heart rate. orbn is different on three counts:
- It plays your music — the local files you own, not a streaming service.
- It understands how you are — using your Oura Ring's overnight recovery/HRV as a daily baseline, nudged by your heart rate, movement, and daytime stress through the day. (The stress signal is recovered from Oura's daily counters between ring syncs.)
- It runs entirely on the device — analysis, matching, and visuals all happen locally on your phone. orbn has no backend and no account of its own; the only thing it ever fetches is your own readings from Oura's API, and nothing about your music or listening leaves the device.
Under the hood, orbn analyzes each song once (tempo, key, energy, mood, genre) and places it in a simple valence–energy space. Your biometric state becomes a target point in that same space, and orbn plays the tracks that fit — with visuals you can just stare at.
The energy (intensity) scale runs calm → mellow → moderate → intense → charged, and that's the word you'll see on the home readout and in "why this track".
No Oura Ring, or don't want to connect one? orbn still works. Pick a mood and it matches songs to that feel instead of your biometrics. Either way it only ever plays the local music you've added to the device.
The moods:
- Default — no override; follow your Oura state (or a neutral feel if there's no ring).
- Happy — bright, upbeat.
- Excited — fast, high-energy — any feeling.
- Chill — mellow, and instrumental only (no lyrics) — made for focus and background listening.
- Sad — slower, downbeat.
- Angry — dark, intense, high-energy.
Why iKKO MindOne? I backed it on Kickstarter in August 2025 because I love small phones and I was looking to replace my Jelly Star. What arrived nine months later was a device without Google Play Services, no OTA updates, and no real path to being a normal phone. Rather than fight for a refund I couldn't get, I was inspired by cyberdecks and decided to turn this into a music player with no distractions that can read my "mood".
Normally, I would not have had the time to build this but I recently started a career break that began in June 2026 and orbn began as an idle whim during the break and snowballed into being my first project during this time. It's partly a thing I genuinely want to use, partly a mechanism to learn in the open. If it's useful or interesting to anyone else, all the better.
I wrote a longer piece on my LinkedIn about how I spent almost 10 years at Twitch and left due to personal reasons, mostly health and general burnout.
If the idea of a music player that actually knows how you're doing seems neat to you, I'd appreciate your support:
orbn was originally built for the iKKO MindOne: a small, near-square Android 15 device with a Cirrus Logic DAC. The goal is a standalone music player with the occasional check of your Oura data.
But it isn't MindOne-only. orbn is written as a general Android app and also runs on other Android phones (verified on a tall, standard-aspect device) — anything device-specific (like the MindOne's DAC tuning) degrades gracefully. Any Android + Oura Ring user can run it, not just iKKO owners.
your music files ──► on-device analysis (tempo / key / energy / mood / genre)
│
Oura Ring ──► daily recovery + intra-day heart rate, movement & stress ──► "how you are" right now
│
match in a valence–energy space
│
play fitting tracks ──► full-screen reactive visualizer
- Kotlin + Jetpack Compose, Android NDK for the native pipeline.
- On-device audio analysis and machine-learning inference for tagging.
- A MilkDrop-style visualizer for the now-playing experience.
- The Oura Web API for biometric data.
- Privacy by design: everything runs locally. Your listening and biometric data stay on the device; orbn talks to the Oura API only to fetch your own data, and to nothing else. See the Privacy Policy for the full picture.
orbn is an Android app. You'll need Android Studio (or the Android SDK + NDK) and JDK 17 or newer.
./scripts/fetch-native-deps.sh # one-time: download prebuilt native deps (Essentia, ONNX Runtime, Eigen, projectM, models)
./gradlew :app:installDebug # build and install on a connected deviceThe native dependencies are large prebuilt binaries kept out of git; the script fetches them from a GitHub Release and unpacks them where the build expects.
There's no prebuilt APK to download — orbn is distributed as source, so you build your own from this repo. (That's partly by design: the app uses your own Oura credentials — see Connecting Oura — and building it yourself is what keeps those yours.) Once you've done the one-time setup above, there are two ways to get your build onto the phone:
- Straight from your computer (simplest): turn on Developer options (Settings → About → tap
Build number seven times) and enable USB (or Wireless) debugging, connect the phone,
and run
./gradlew :app:installDebug— it compiles and installs in one step. - As a standalone file: run
./gradlew :app:assembleDebugto produce an APK atapp/build/outputs/apk/debug/app-arm64-v8a-debug.apk, copy it to the phone, and tap it to install. The first time, Android asks you to allow "install unknown apps" for whatever opened the file (your files app or browser) — that's the sideload prompt.
This is a debug build, which is fine for personal use.
orbn plays the local files you own. There are two ways to get them in:
- In-app (recommended, works on any phone): tap "add music" on the home screen (shown while your library is empty), or ⚙ settings → "Add music" anytime after that, and pick the tracks from anywhere on your device — Downloads, internal storage, an SD card, or a cloud provider.
- Manually: copy audio files over USB into the app's folder at
Android/data/com.earlyspark.orbn/files/Music/. Note that some phones hideAndroid/datafrom a computer's file browser — if you can't see it, use the in-app picker instead (or copy to your Downloads folder and import from there).
Either way, orbn copies the files into its own folder — your originals are never touched or
modified. Because they live inside the app, uninstalling orbn deletes its copies (re-importing is
quick). Supported: mp3, flac, m4a, aac, ogg, wav.
Removing a song: while a track is playing (or paused), tap the trash icon in the bottom corner and tap again to confirm — orbn deletes the file from the phone (its Music folder), clears the song's listening history, and advances to the next pick. If the song came from somewhere else — your computer, Downloads, a cloud provider — that source copy isn't touched, so you can re-import it anytime.
How analysis works: when you add music, orbn analyzes each track on-device — tempo, key, energy,
mood, and genre — and nothing is uploaded. The home screen and a notification show the progress
(tagging your library… 3 / 12), and a track becomes available to play once it's been analyzed. It's
CPU-heavy work — on the order of tens of seconds per track — so a large library tags itself in the
background over time (even while you listen), and it resumes automatically if interrupted.
To use the biometric features, you supply your own Oura developer app credentials. Register an application at developer.ouraring.com/applications
with the redirect URI com.earlyspark.orbn://oauth2redirect. When the registration form asks
which scopes to enable, include at least the ones orbn requests — email, daily,
heartrate, tag, session, spo2, and stress (authorization fails if the app requests a
scope your registration doesn't enable). Then add the values to local.properties (which is
gitignored and not committed):
OURA_CLIENT_ID=your_client_id
OURA_CLIENT_SECRET=your_client_secret
OURA_REDIRECT_URI=com.earlyspark.orbn://oauth2redirectThe build injects these into BuildConfig at compile time; they are not hardcoded in source.
Without them the app still builds and plays music — it just shows "Oura: add credentials" instead
of biometric data.
Once connected, orbn reads your data on app-open and at each track change — including while the screen is off — and shows the time of the freshest reading. For this to stay current, turn on background sync in the Oura app — your ring only reaches Oura's cloud through that app, so with background sync off orbn can only see data from the last time you manually opened Oura.
The bundled visualizer presets (a curated subset of projectM's Cream of the Crop) vary in how hard they push the GPU. Measured on the MindOne (Dimensity 7050, ~90 Hz display):
| fps (best) | Preset | |
|---|---|---|
| 22 | royal-mashup-244 |
🔴 heavy |
| 28 | evet-flexi-x32-astroluxn777 |
🔴 heavy |
| 30 | royal-mashup-257 |
🔴 heavy |
| 45 | tripgnosis-goldenglowstick |
🔴 heavy |
| 49 | royal-mashup-276-isosceles-edit |
🔴 heavy |
| 51 | royal-mashup-287 |
🟡 borderline |
| 53 | martin-n-adamfx-hardcore-mix-collision-in-myself |
🟡 borderline |
| 60–72 | suksma-kaeuldrone-disphignunt-sheviski, syst3mfailur-satanic-ring-v2-nz-isosceles-edit2, 306-nz-ain-no-hoehoe, martin-underwater-cathedral-1, tonymilkdrop-nuclear-flexi-help-out-alien-comple, flexi-adamfx-geiss-and-rovastar-tokamak-tng-syne, suksma-mtn-flx-flacc-choilan-roam |
🟢 fine* |
| 75–92 | flexi-rovastar-fractopia-blame-hexcollie, martin-lightning, 271-nz, 211-wave |
🟢 smooth |
* The 60–72 group is likely smoother in practice — each preset got only ~4 s in the sweep, so the one-time shader-compile hitch on switching dragged its average; with a longer dwell several of these sit near 80 fps.
Keeping a heavy preset is low-risk — it won't crash, freeze, harm the device, or stall audio; the
cost is just choppier visuals plus more battery and heat, and on a small fanless phone a heavy preset
over a long session can warm the device and thermal-throttle (it self-protects — no damage). To drop
one, delete its .milk file from app/src/main/assets/presets/ and rebuild.
On-device music analysis → background tagging of your library → playback → Oura integration → biometric matching → the full-screen reactive visualizer → a manual mood picker ✅ — v1, done — → intra-day stress as a matching signal + a body timeline view ✅ — → a settings menu ✅ → accessibility checks (reduced-motion option ✅) — v2 → refinement & tuning (ongoing) → more.
✅ v1 is feature-complete: the full loop works end to end — it reads your body, plays music to match, and visualizes it. On real hardware, orbn scans and analyzes your library entirely on-device (tempo, key, energy, mood, genre), connects to your Oura Ring to read your recovery, heart rate, movement, and daytime stress into a "how you are right now" signal, and builds a play queue that fits that signal — sampled for variety, ordered to flow, and mindful of what you've recently played so it doesn't repeat. Recent tension leans the music more intense and recovery leans it calmer (orbn mirrors you, it doesn't manage you). Pull down to re-tune the queue to right now, or swipe to set a mood (happy, chill, sad, excited…) when you want to override what your body says and pick the feel yourself. Swipe up on a playing track to see why it was picked — and swipe up again for a day graph of your body: heart rate, movement, and stress, drawn from the same data the matcher uses. Now-playing is a full-screen MilkDrop-style visualizer (projectM) that reacts to the live audio — tap to play/pause, double-tap to change the visual (a library of presets you cycle through), long-press to exit. Plays back hi-res to the iKKO's DAC when the case is attached.
- 🔜 v2 — in progress: a settings menu has landed — reach it from the gear on the home screen — with a reduced-motion toggle (holds the mascot still), an option to suppress the visualizer's swipe-open drawers, and an "add music" entry to import more songs anytime. Still to come: the rest of the accessibility checks (TalkBack, touch targets, contrast). After that, it's refinement — polish, QA, and tuning how well songs match your state.
Built by RayAna (@earlyspark).
orbn is licensed under the GNU Affero General Public License v3.0 (AGPLv3). You're free to use, study, modify, and share it — but any distributed or network-deployed derivative must also be open-sourced under AGPLv3. As the sole copyright holder, the author can grant separate commercial licenses on request.
Copyright © 2026 RayAna (@earlyspark).
Standing on the shoulders of open source — including Essentia (audio analysis), ONNX Runtime (on-device inference), and projectM (MilkDrop-style visuals). The bundled visualizer presets are a curated subset of projectM's Cream of the Crop pack (community MilkDrop presets).
