Play an Online Theremin with Your Hands

Start the Online Theremin

Place your laptop or phone where the front camera can see your upper body and both hands. Use even light from in front of you, avoid a bright window behind you and leave some empty space above your shoulders. Press Start and allow camera access when the browser asks.

Begin with your speakers at a moderate level. Raise both hands into the frame and wait until the tracking indicators respond. The instrument starts in Theremin mode on this page, so you do not need to count fingers or form chord shapes.

• Move the right hand upward for a higher pitch and downward for a lower pitch.
• Move the left hand upward for more volume and downward to fade out.
• Use the on-screen mute before changing camera position or audio output.
• Keep wrists visible and movements smooth for steadier control.

Control Pitch and Volume Independently

Treat the two hands as separate axes. First lower the left hand until the sound is quiet, place the right hand near the pitch you want, then raise the left hand slowly to reveal the note. This simple fade-place-fade technique prevents loud glides between phrases.

Pitch follows vertical position rather than finger count. Small right-hand movements make finer changes, while large sweeps create siren-like glissandos. There are no frets or keys to lock intonation, so use the pitch display and your ears to settle on a note.

Practise an octave without relying on a keyboard grid. Lower the left hand until the tone is nearly silent, then move the right hand until the display is close to 220 Hz and raise the left hand gently. Fade down again, move the pitch hand toward 440 Hz and reveal the second tone. Those frequencies are an octave apart, so the second should sound like the same pitch class at twice the frequency. Reverse the exercise from 440 toward 220 without making one loud continuous sweep. The display is a guide rather than a pitch snap; stop moving for a moment and make small height corrections if the value drifts. This exercise separates precise right-hand placement from the left-hand fade used to enter each note cleanly.

Make Notes Smoother and More Stable

A webcam cannot measure hand position as precisely as dedicated theremin hardware. Rest your elbows lightly near your body, move from the forearm and avoid crossing one hand in front of the other. A plain background and consistent light help the tracker keep each hand assigned correctly.

If the tone jitters, step slightly farther from the camera so your full hands remain visible. Close other camera-heavy tabs, enable the low-performance option on slower devices and pause between experiments instead of making rapid movements outside the frame.

What This Virtual Theremin Can and Cannot Do

This instrument is useful for learning two-hand pitch-and-volume coordination, making sound effects and exploring continuous melody. It works without an account, download, MIDI controller or microphone, and it processes hand tracking during the active browser session.

It does not reproduce the electromagnetic field, antenna response or exact timbre of an acoustic theremin. It also does not record audio automatically. For discrete chords instead of continuous pitch, switch to Gesture mode or open the chord-player guide.

Play hand-controlled chords → · Fix a silent session →