⚡ VoltHalt

VoltHalt is a light-weight, open-source Android app that monitors your battery level in the background and alerts you with a loud alarm or a custom Text-to-Speech voice message when your battery reaches a target charge or drops too low.

Unlike built-in manufacturer limits, VoltHalt works on any Android 8.0+ device without root, features a convenient Quick Settings (QS) Tile, and operates 100% offline with zero data collection or internet permission.

Battery Health Tip: Keeping lithium-ion batteries between 20% and 80% significantly extends their overall lifespan. VoltHalt automates this for both charging and discharging.

VoltHalt is built with absolute privacy in mind:

• NO android.permission.INTERNET requested or required.
• Zero Data Collection: No telemetry, no analytics, no ad networks, no tracking scripts.
• Zero External Network Calls: Everything runs completely locally on your device.
• Maximum Battery & RAM Efficiency: No background network wake-ups or server polling.

VoltHalt is packed with essential features to keep your battery healthy while giving you total control:

VoltHalt includes a native Android Quick Settings (QS) Tile for fast access without needing to launch the app UI:

• One-Tap Toggle: Swipe down your Android notification shade and tap the VoltHalt tile to instantly turn battery monitoring on or off.
• Real-Time Sync: Tile state updates automatically to reflect whether active background monitoring is running ("Alarm On" / "Alarm Off").
• Long-Press Shortcut: Long-pressing the VoltHalt Quick Settings tile directly opens the app settings screen.
• How to Add:

1. Swipe down twice from the top of your screen to expand Quick Settings.
2. Tap the Edit (pencil) icon.
3. Scroll down to find VoltHalt, drag it into your active tiles, and tap Done.

Note: Since this APK is distributed directly on GitHub, enable "Install from unknown sources" in your Android settings if prompted.

Settings → Security → Install unknown apps → Allow for your browser or file manager.

• Language: Kotlin
• UI Framework: Jetpack Compose + Material 3
• Architecture: Single-Activity Compose with DataStore state management
• Persistence: Preferences DataStore
• Background Service: Android Foreground Service (BatteryService) with BroadcastReceiver
• System Integration: TileService for Quick Settings & TextToSpeech engine for voice alerts
• Minimum SDK: Android 8.0 (API 26)
• Target SDK: Android 14 (API 34)

• Android Studio Hedgehog (2023.1.1) or newer
• JDK 17 / JDK 8+
• Android SDK 34

# 1. Clone the repository
git clone https://github.com/im-atp/VoltHalt.git

# 2. Open in Android Studio
# File → Open → select the VoltHalt folder

# 3. Let Gradle sync complete, then build
# Build → Make Project   (Ctrl+F9)

# 4. Run on your device or emulator
# Run → Run 'app'   (Shift+F10)

# In Android Studio:
# Build → Generate Signed Bundle / APK → APK → follow the wizard

VoltHalt/
├── app/
│   └── src/main/
│       ├── java/com/im_atp/volthalt/
│       │   ├── MainActivity.kt          # App entry point & setup routing
│       │   ├── AlarmActivity.kt         # Full-screen lock screen alarm overlay
│       │   ├── BatteryService.kt        # Background sticky broadcast monitoring service
│       │   ├── AlarmPlayer.kt           # Ringtone audio & Text-to-Speech playback manager
│       │   ├── AlarmTileService.kt      # Android Quick Settings (QS) Tile handler
│       │   ├── PreferencesManager.kt    # DataStore Preferences for settings & TTS phrases
│       │   └── ui/
│       │       ├── screens/
│       │       │   ├── MainScreen.kt    # Home dashboard, battery level, alarm cards & preview
│       │       │   ├── SettingsScreen.kt# Max/Low alarm targets, volume, TTS, themes & setup
│       │       │   └── SetupScreen.kt   # Permission onboarding wizard
│       │       └── theme/
│       │           └── Theme.kt         # Material 3 dark/light design system
│       ├── res/                         # Vector icons, string resources & XML configurations
│       └── AndroidManifest.xml
├── build.gradle.kts
├── settings.gradle.kts
└── README.md

VoltHalt requests only what is essential for reliable alarm functionality:

Zero Internet Permission: android.permission.INTERNET is NOT included in the app manifest. VoltHalt cannot send data anywhere.

Contributions, feature requests, and bug reports are welcome!

1. Fork this repository
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Commit your changes: git commit -m 'feat: add amazing feature'
4. Push to your branch: git push origin feature/amazing-feature
5. Open a Pull Request

Open an Issue and include:

• Your Android version & Device model
• Detailed steps to reproduce
• Expected vs actual behavior

MIT License

Copyright (c) 2026 im_atp

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.