SynthBridge KeyCaster

Turn any USB or Bluetooth keyboard into a MIDI controller for your DAW.

SynthBridge 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.

🎹 PLAY NOTES WITH YOUR KEYBOARD
No more tiny on-screen piano. KeyCaster lets you use a real full-size keyboard — the one already on your desk — as a MIDI controller. Works with any standard USB (OTG) or Bluetooth HID keyboard.

🎛 FIVE BUILT-IN PRESETS
• Piano — 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 your own presets from scratch, duplicate a built-in to tweak, or import mappings shared by a friend. Every key can trigger a Note, a Chord (multiple notes at once), a Control Change (momentary or toggle), a Program Change, or a Pitch Bend. Capture any key with one tap; adjust channel, note, velocity and mode with sliders.

🔊 WORKS WITH YOUR FAVOURITE APPS
KeyCaster registers as a virtual MIDI input device named "SynthBridge KeyCaster" in the system. Any MIDI-capable Android app can pick it up:
• SynthBridge (our companion mobile synth)
• FL Studio Mobile
• BandLab
• Garageband
• KORG Gadget
• Any other MIDI host

🎚 LIVE VELOCITY CONTROL
A global velocity slider on the home screen drives the velocity of every built-in preset in real time — add expression without editing a single mapping.

📲 KEEPS PLAYING IN THE BACKGROUND
Enable the accessibility service and KeyCaster will keep reading your keyboard while your DAW is in the foreground. Notification-shade shortcuts let you cycle between presets without leaving the app you are recording in.

👀 VISUAL KEYBOARD DIAGRAM
The on-screen keyboard layout highlights which keys are mapped to what — Note, Chord, CC, Program Change, Pitch Bend — with distinct colours, and lights up each key as you press it. Tap any key to inspect or edit its mapping.

📦 IMPORT / EXPORT PRESETS
Share mappings as simple JSON files via any file picker. Perfect for backing up your custom rig or passing a setup between devices.

🚀 ULTRA-LOW LATENCY
Built on Android's native MIDI framework (android.media.midi). Key event to MIDI byte in under 5 ms — good enough for live playing.

🔒 PRIVACY
All keyboard processing happens on device. No data leaves your phone. No account, no ads.

★ PART OF THE SYNTHBRIDGE SERIES
KeyCaster is designed to pair with SynthBridge, our mobile MIDI sound module that turns your phone into a 261-instrument sound source. Both apps work standalone — use KeyCaster with any MIDI-capable app you like.

Minimum Requirements:
• Android 7.0 (API 24) or higher
• External keyboard via USB OTG or Bluetooth HID

Permissions:
• Accessibility service (optional, for background keyboard capture)
• Post notifications (Android 13+, for the preset-switch shortcut)
• Foreground service (keeps the shortcut notification alive while you are in other apps)