The starting point
A theremin is the only instrument you play without touching. THEREMIND is one you play with a webcam: right hand for pitch, left hand for volume, faithful to the real thing. Free Play gives you the instrument and a tuner. Learn mode walks you through Unit 1, six lessons that take a first-time player from finding a note to vibrato and a short piece.
What I built
MediaPipe hand tracking drives a Web Audio oscillator directly, no audio library. A One Euro filter keeps the pitch from jittering, and three pitch-assist levels (off, soft, full) let a beginner sound like music within ten minutes. Vanilla JavaScript on Vite with a Three.js instrument model, and nothing stored anywhere but localStorage.
Where it landed
The production build is playable directly on this site. Camera frames are processed locally in the browser and are never uploaded.