SynthBridge KeyCaster
Keyboard → MIDI Controller
Platform
Android 7.0+
Latency
< 5 ms
Built-in Presets
5
Languages
11
Screenshots
About
KeyCaster transforms any Bluetooth or USB computer keyboard into a virtual MIDI controller for Android. Connect a keyboard, pick a preset, and every key you press streams straight into your favourite music app with sub-5 ms latency.
Designed as a companion to SynthBridge, KeyCaster works with any MIDI-capable Android app — FL Studio Mobile, BandLab, Garageband, KORG Gadget — registering itself as a virtual input device named "SynthBridge KeyCaster".
All features are free. No accounts, no ads, no data collection.
Five Built-in Presets
- Piano — C Major: QWERTY row mapped to a 2-octave C major scale (classic FL Studio layout)
- Drum Pad 4×4: 16 keys trigger a full GM drum kit like an MPC
- DJ Controller: Function and number keys send MIDI CC for volume, filter, and effects
- Combo: Number row plays drums, QWERTY plays piano, modifier keys drive CC
- Chord Pack: One key = one chord, with diatonic triads and 7th chords in C major
Custom Mappings
- Create new presets from scratch, duplicate a built-in to tweak, or import mappings shared by a friend
- Trigger a Note, a Chord (multiple notes), Control Change (momentary or toggle), Program Change, or Pitch Bend
- Capture any key with one tap; adjust channel, note, velocity, and mode with sliders
- Import and export presets as simple JSON files via the system file picker
Performance Features
- Global velocity slider drives the velocity of every built-in preset in real time
- Visual keyboard diagram highlights each key's mapping; lights up as you play
- Accessibility service keeps reading the keyboard while your DAW is in the foreground
- Notification-shade shortcuts let you cycle presets without leaving the recording app
Privacy
All keyboard processing happens on your device. Nothing leaves your phone — no account, no ads, no analytics.