Air theremin: webcam theremins you can play in the browser
Short answer: an air theremin is a webcam theremin: a theremin simulated in the browser, where your hands in front of the camera replace the antennas. The best-known one is Air Theremin by Pavel Gurov, which reached the Hacker News front page in August 2026 with more than three hundred votes. To play one right now, open HandSynth's air theremin online; it covers the same ground with note snap, a mouse mode and MIDI out.
Air Theremin (theremin.bizibah.com)
- Inputs: webcam hands, phone gyroscope (tilt for pitch and volume, with calibration) and mouse.
- Gestures: spread hands for volume, raise for pitch, palms together for silence, lean back to darken the tone.
- Sound: four waveforms (sine, triangle, warm, reed), vibrato, tremolo, echo and reverb, a note snap option and a recorder with pause.
- Tech: MediaPipe Hand Landmarker compiled to WebAssembly, a single HTML file with no build step, MIT licensed. The author added a bass harmonic exciter so low notes carry on phone speakers.
- What people said: praise for the mapping and for nothing leaving the machine; complaints about a dense interface, notes hanging briefly when a hand vanished, and stepped pitch in phone mode, which the author fixed by reading the sensor every frame.
Other browser theremins
- theremin.app and theremin.site: mouse-driven, the long-standing results for "online theremin".
- TermenVox: another webcam theremin released the same week as Air Theremin.
- Older mouse theremins from femurdesign, pirillo and bigjobby still work and need no camera.
How HandSynth's theremin compares
| Feature | Air Theremin | HandSynth |
|---|---|---|
| Webcam hands | yes | yes |
| Phone gyro | yes | no (touch instead) |
| Mouse and touch | mouse | mouse, touch, keyboard |
| Note snap to a chosen scale | snap only | major, minor, pentatonic, blues, chromatic |
| Effects | vibrato, tremolo, echo, reverb | vibrato by pinch, reverb |
| Recording | yes | WAV |
| MIDI out | no | yes (Chrome, Edge) |
| Chord mode | no | yes |
| Open source | MIT | no |
If you want the richest theremin tone and phone tilt play, use Air Theremin. If you want to stay in a scale, play chords with the other mode, drive a synth in your DAW, or play without a camera, use HandSynth's theremin. Either way the theremin technique is the same: keep the pitch hand open and steady, and control volume with the other hand rather than by moving the pitch hand away.
How the webcam becomes an instrument is covered in how a hand tracking synth works. If the camera stays dark or there is no sound, the troubleshooting guide has a fix for each symptom.