An instrument you don't have to buy, hold or tune — your bare hands in the air play chords, melodies and drums, and nothing you do ever leaves your machine.
Play it now → manos-instrument.vercel.app — open it in Chrome or Edge and allow the camera.
It does not imitate a guitar or a piano — a D chord is a different shape on every instrument anyway. Instead, your hands control the music itself:
| Gesture | What it does |
|---|---|
| 1–4 fingers | The scale degree: I, II, III, IV |
| Thumb out | Adds five: V, VI, VII |
| Lean the hand | minor ← plain → seventh |
| Raise / lower | The octave |
| Fist | Silence |
| Other hand | Height is volume, opening it is brightness |
| Other hand: 2 fingers | Sevenths family — maj7, m9, 9 |
| Other hand: 1 finger | Colours — sus2, sus4, 6, m6 |
| Slide to the edge | ♭ on the left, ♯ on the right — chords outside the key |
The same lean that plays an A major turns it into Am, A7 or Amaj7. That is the move a musician makes when they want a chord to ache — turned into something you feel with your wrist.
- Play any song. Paste a chord chart — chords alone or over lyrics. It picks the key where the song needs the fewest tricks, shows the gesture for every chord, lights up green when you nail one, and follows you as you play.
- 13 scales — from a guided five-note scale where nothing can clash, through harmonic minor, blues and the church modes, hirajoshi and hijaz, to the nine solfeggio frequencies (174–963 Hz) for sound-bath work. Tuning at 440 or 432 Hz.
- 11 synthesized sounds in four families — pads and voices, keys and plucks, bells and glass, bass and drones. In duet mode each hand can be a different instrument.
- Conducted drums. The beat keeps time on its own clock; your hand conducts it — fingers for density, height for volume, a fist mutes it right on the bar.
- Record your take — sound as 24-bit WAV ready for any DAW, or a shareable video of the whole performance, each with or without your own voice from the microphone. Headphones keep the voice clean. Nothing is uploaded; files save straight to disk.
- MIDI out (Chrome/Edge) — the gestures play your synths: GarageBand, Ableton, hardware. Volume rides CC7, brightness CC74. On a Mac, enable the IAC Driver in Audio MIDI Setup and pick it as the output.
- Melody mode, a live chord map, reverb / delay / chorus / drive, and an adjustable response feel. English and Spanish.
- The first visit hangs for a few seconds. It is downloading the hand-tracking model (~8 MB) once; your browser caches it after that.
- A held chord re-strikes on its own with plucks, bells and glass. Sounds that decay are re-struck by design — it reads as tremolo, or strumming.
- The sound answers a beat after your hand. That is the Smoothness slider trading speed for glide; pull it left for immediate response.
- "the /B bass will not sound" on a song card: slash basses are not playable yet — the chord itself is complete. Chords that sound identical in a row (G · G/A · G/B) share one card that shows every name.
- Your fist is not being ignored — it just doesn't need to be tight. Fingers curled loosely toward the palm count as a fist.
- The MIDI checkbox says your browser can't. Only Chrome and Edge ship Web MIDI; the built-in sounds work everywhere.
- Everything runs inside your browser. The camera image and your audio are never uploaded — there is no server to upload to.
- No accounts, no analytics, no cookies. Your settings and pasted song live in your browser's local storage, on your machine.
- The only network request is the one-time download of the hand-tracking model. That claim is enforced by policy, not just promised — details in SECURITY.md.
- Recordings are assembled locally and saved straight to your disk.
npm install
npm run devOpen http://localhost:3004 and allow the camera (it needs HTTPS or localhost).
npm run build produces a static dist/ that deploys to any static host.
The 🐛 button in the app opens a GitHub issue with the technical details already filled in — or just open one here.
If this was useful and you'd like to support the project: