Choose a chord with one hand and strum the air with the other. Hand Chord watches your hands through the camera: a gesture or a finger count picks a chord, and moving your other hand's index finger across twelve virtual strings plays its notes. It sends MIDI, so any instrument can be its voice.
How it plays
The video takes most of the face, mirrored, with your hands highlighted.
- The chord hand (left by default) selects a chord. Six recognised gestures each recall a chord: Open Palm C, Pointing Up D, Thumb Up G, Victory A, I Love You F and Thumb Down B♭. Alternatively, count fingers: an open palm is C, and one to four fingers recall D, E, F and G. A closed fist is silence: it releases everything and pauses strumming until you open your hand.
- The strumming hand (right by default) plays the chord's notes across twelve strings, repeated over several octaves around the chord. Sweep across them like a strum, or pick one string back and forth to repeat a note. A fast sweep plays every string it crosses, in order. Strings further to the right play louder.
The chord circles orbit the left of the video and show which chord is active. A history of the last sixteen chords sits inside the frame.
Without a camera
Click a chord circle to hold that chord, then hover or click across the strings, or use the keyboard. Click the active circle again, or the release button, to let go. Playing a MIDI note also selects a chord: each of the twelve note names recalls its own chord from the bank.
The chord bank
Each of the twelve note names has a chord in a saved bank. Palette builds that bank with the same tools as the Harmonizer module: weight the twelve pitch classes, choose how simple, colourful or tense the chords should be, how many have two, three or four notes, and how much variation to allow. Generate fits a new bank to those settings, a seed number recreates an exact bank, and each slot can be re-rolled on its own. Chords are close, root-position voicings within an octave, in octave 3 by default.
The presets are a quick way to hear the range: Expressive, Gentle, Short strum, Seventh chords, Minor ballad, Power chords and Sustained melody.
Performance settings
- Velocity follows the strumming hand's horizontal position (the default), how fast it moves, or stays fixed.
- Strum length sets how long each plucked note lasts.
- Chords and strummed notes go out on separate MIDI channels, 1 and 2 by default, so they can play different instruments. On the website, the playback bar pairs a piano for chords with a kalimba for the strings; the Hand Chord duet rack sends chords to FM Keys and the strings to OSC Mini.
- You can swap which hand does what, choose gestures or finger counts and how many chord slots to use, label the circles with emoji, Roman numerals or chord names, and let the chord hand's height change the octave (off by default).
View options chooses the video look (Thermal by default, or natural), the preview quality (Fast, Balanced or Best), whether strings show their note names and whether they vibrate when struck. The camera button beside it starts, stops and restarts tracking.
Privacy and limits
Camera frames and hand landmarks stay in your browser. Only hand tracking and gesture recognition run; no face or body model is loaded.
Tracking depends on your camera, lighting and computer. Very fast motion that reverses between two camera frames cannot be detected. Hand Chord makes no sound itself; use the playback bar's instrument or connect an instrument in a rack.
