Dictate

A native Android app that turns a volume-button combo into a lock-screen voice transcription pipeline. Press both volume keys within 300 ms while the screen is locked (or unlocked) to launch a transparent overlay that captures speech via Android's built-in SpeechRecognizer, shows the live partial transcript, and posts the final text as JSON to a webhook you configure.

How it works

[Vol+ & Vol- within 300ms] -> ButtonInterceptorService (AccessibilityService)
                                          |
                                 TranscriptionActivity (overlay above lock screen)
                                          |
                                SpeechRecognizer (live partial results)
                                          |
                                 [Stop & Send] -> WebhookClient (OkHttp POST)

The webhook receives a JSON body:

{
  "timestamp": 1717701830,
  "text": "The transcribed text goes here."
}

Requirements

• Android device running API 26 (Android 8.0) or higher
• Android Studio (or just the Android SDK + JDK 11) for building
• An internet-reachable endpoint that accepts a JSON POST (your webhook)

Building

The project includes the Gradle wrapper, so you don't need Gradle installed locally. From the project root:

# Debug build
./gradlew assembleDebug

# Release build (configure signing as needed)
./gradlew assembleRelease

The resulting APK is at app/build/outputs/apk/debug/app-debug.apk.

On first run Gradle will download the distribution and dependencies, which can take a few minutes.

Building with Android Studio

Open the project folder in Android Studio and pick Run > Run 'app' with a connected device selected. Android Studio handles the SDK path via local.properties automatically.

Installing on a device

Enable USB debugging on the device and connect it, then:

adb install -r app/build/outputs/apk/debug/app-debug.apk

First-time setup

1. Open the Dictate app from the launcher.
2. Enter your webhook URL (e.g. https://your-server.com/api/transcribe) and tap Save.
3. Grant the Record audio permission when prompted.
4. Enable the Dictate accessibility service:
   • Go to Settings > Accessibility > Installed services > Dictate and turn it on. This is required so the app can intercept hardware key events while the device is locked.

Optional but recommended: disable battery optimizations for Dictate so Android's Doze mode doesn't kill the background service:

• Settings > Apps > Dictate > Battery > Unrestricted

Using it

1. Lock the device (or leave it unlocked).
2. Press Volume Up and Volume Down within 300 ms of each other. A toast ("Dictate: Listening...") appears and a translucent overlay shows the live transcription.
3. Speak; partial results update on screen in real time. Recognition restarts automatically after each phrase so you can dictate multiple sentences.
4. Tap Stop & Send (or anywhere on the overlay) to stop, send the assembled transcript to your webhook, and dismiss the overlay.

Permissions

Permission	Why it's needed
RECORD_AUDIO	Access the microphone for speech recognition.
INTERNET	POST the transcript to your webhook.
BIND_ACCESSIBILITY_SERVICE	Intercept hardware volume key events globally, including from the lock screen.

Project layout

app/src/main/java/com/dictate/
  ButtonInterceptorService.java   # AccessibilityService: detects the volume combo
  TranscriptionActivity.java      # Lock-screen overlay + SpeechRecognizer lifecycle
  WebhookClient.java              # OkHttp async POST of the transcript
  SettingsActivity.java           # Configure and persist the webhook URL
app/src/main/res/                 # Layouts, strings, themes, accessibility config
spec.txt                          # Original technical specification

Notes & caveats

• SpeechRecognizer can be slow to initialize when the device is deeply asleep. If you see initialization lag, a temporary WakeLock acquired in the accessibility service right before launching the activity usually helps.
• The accessibility service consumes volume key events only while transcription is not active, so normal volume changes are unaffected outside of a session.
• local.properties is intentionally git-ignored because it contains the absolute path to your local Android SDK install.