Hear the pulse first. The audio clock sets the tempo, not the camera.
Free online gesture synth
Gesture Synth
Your hand can wobble.
Your beat won’t.
Raise a finger. Hear a chord. Beat Lock keeps every change in time.
No account · Nothing is uploaded
Mouse ready
Free play
Choose camera or move across the chord pads.
C
I
Target
I
Playing
I
Mouse ready
No camera needed
Beat Lock ready
Keyboard: press 1–5 for chords, Space to release.
One input. Two outcomes.
Hear what Beat Lock changes
A camera notices every small correction in your hand. Music doesn’t need to play every one. Hear the same uneven gesture synth input with instant switching, then with Beat Lock.
From movement to harmony
Play chords with your hands
This gesture synth uses one hand and five choices. Hold up one to five fingers for chord degrees I through V. Raise your hand for more intensity; make a fist to release the sound. You can start playing before you know the chord names.
In Major mode, every chord stays in one key. Minor mode changes the mood without changing the controls. Pentatonic mode uses open fifths for a lighter, more spacious sound. Change the root or sound whenever you like; the gesture synth mapping stays the same.
Camera input is optional. Mouse, touch, and number keys use the same audio engine, challenge, and score. Use them when a webcam is missing or blocked—or when you want to learn the mapping before allowing camera access.
Learn every gesture and fallback controlOne fingerI
Two fingersII
Three fingersIII
Four fingersIV
Five fingersV
Four bars and a target
Try a gesture chord challenge
The default gesture synth challenge is a four-bar I–V–IV–V progression at 80 BPM. After a four-beat count-in, show the requested finger count before the next bar begins.
The next chord appears before the bar changes, so there’s time to make the pose.
A stable hand gesture waits in the rail until the beat arrives.
See a beat-by-beat timeline, then save files made in your browser.
Between camera input and sound
How this gesture synth stays on beat
Read a stable gesture
The browser tracks hand landmarks, classifies the finger count, and waits for three matching frames. A short hysteresis window filters rapid back-and-forth changes. The stage reports whether it found a hand and whether the gesture is stable.
Queue the next chord
A confirmed gesture becomes the pending chord. The current chord keeps sounding while one uncertain frame passes. The pending label shows what will play next, with time to correct the pose.
Change on the audio clock
Web Audio schedules the change against its own clock at the next beat boundary. The visual pulse follows that boundary. Beat Lock separates detection time from musical time. Instant mode stays available in Free Play when you want a direct response.
One vocabulary across every input
Gesture synth controls
Camera gestures, mouse movement, touch pads, and number keys all use the same chord system.
1–5 fingers
Chord degree I–V
Hand higher or lower
More or less intensity
Fist or Space
Release the chord
Mouse left or right
Choose a chord
Mouse up or down
Change intensity
Stable new gesture
Queue the next beat
A performance you can inspect
Record your performance and export MIDI
The challenge records the visible gesture synth stage and generated audio locally when the browser supports WebM capture. It does not upload a camera recording to create your result.
Results show Match, Timing, and Stability separately. A sixteen-beat timeline pairs each target with the chord that played. Download the stage clip or export a standard MIDI file for a DAW. MIDI contains musical events, not video frames or hand landmarks.
Recording formats vary by browser. If video capture is unavailable, the result explains the limitation and keeps MIDI available.
Camera in. Landmarks out. Nothing uploaded.
Camera privacy and browser support
Camera access begins only after you press Start with camera and accept the browser permission request. The video element, hand landmark model, synthesizer, score, recording canvas, and MIDI generator run on your device. Gesture Synth does not need an account, a video upload, raw landmarks, or face data to complete the challenge.
A good camera result still depends on practical conditions. Keep your whole hand in frame, face a window or lamp, and leave enough space between fingertips. If the page cannot find a hand, it keeps the current chord briefly instead of cutting the sound on the first missing frame. A longer loss releases the chord smoothly.
Camera and recording APIs differ between browsers. Gesture Synth checks them at runtime. If a camera or video codec is unavailable, use Mouse Mode or MIDI. The privacy page covers the data flow; the gesture guide covers camera troubleshooting.
Straight answers before camera access
Gesture Synth FAQ
What is a gesture synth?
A gesture synth is a synthesizer controlled by visible movement instead of a hardware keyboard. This gesture synth maps one to five fingers to chord degrees, then uses hand height for intensity. Mouse, touch, and keyboard controls provide the same musical mapping without a webcam.
How do I play chords with hand gestures?
Start the camera, place one hand fully inside the frame, and hold up one to five fingers. Wait until the Next label confirms the gesture. With Beat Lock active, the chord changes on the next beat instead of switching on the first detected frame.
Is my camera video uploaded?
No. Hand landmark detection and sound generation happen in your browser. The camera stream is used on your device and is not sent to a Gesture Synth server.
Can I use Gesture Synth without a webcam?
Yes. Choose Mouse Mode, tap the chord pads, or press number keys 1–5. Those inputs use the same gesture synth engine, challenge, scoring, and export flow as the camera.
Can I export the performance as MIDI?
Yes. Finish a challenge and download a standard MIDI file containing the beat-locked chord events. The file can be opened in common MIDI-capable music software.
Which browsers support Gesture Synth?
The page checks Web Audio, camera, recording, and canvas capture support when you use them. If camera access or WebM recording is unavailable, Mouse Mode and MIDI provide a fallback rather than a blocked screen.
Why does Beat Lock feel different from Instant mode?
Instant mode applies each stable gesture as soon as it is confirmed. Beat Lock queues that gesture for the next musical boundary. The response is intentionally less immediate, but chord changes align with the groove and small corrections are less likely to sound like extra notes.
Gesture Synth is ready when your hand is