Karoo Dynamic Headphones

Smart music control for Karoo 3 cycling computers. Automatically manages your music based on riding speed.

Features

• ⏯️ Auto-pause music when you stop (Speed = 0)
• 🔊 Dynamic volume adjustment (louder at speed, quieter when stopped)
• 🎧 Works with any Bluetooth headphones
• 🚴 Seamless integration with Karoo 3
• ⚙️ Configurable pause threshold (0.1 - 5.0 km/h)
• 🔄 Switch between Dynamic and Normal mode

Installation

Download APK (Release 0.1)

📥 Download app-release-0.1.apk

Manual Build

Requirements

• Android Studio (latest version)
• Android SDK 34
• Karoo 3 with USB debugging enabled

Build Steps

Option 1: Android Studio

1. Clone this repository
2. Open in Android Studio
3. Connect Karoo 3 via USB (enable USB debugging first)
4. Click "Run" (▶️) to build and install

Option 2: Command Line

# Build debug APK
./gradlew assembleDebug

# Or build release APK
./gradlew assembleRelease

# APK location:
# Debug: app/build/outputs/apk/debug/app-debug.apk
# Release: app/build/outputs/apk/release/app-release.apk

Install via ADB:

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

Setup on Karoo 3

Enable USB Debugging

1. Go to Settings → About
2. Tap "Build Number" 7 times
3. Go back → Developer Options
4. Enable "USB Debugging"

Install APK

adb install karoo-dynamic-headphones.apk

Grant Permissions

The app needs these permissions:

• Bluetooth (for headphone control)
• Media control (to pause/play music)
• Location (for speed sensor access)

Usage

Dynamic Mode (Default)

• Music pauses when you stop (below configured threshold)
• Volume increases with speed
• Volume decreases when stopped

Normal Mode

• Fixed volume level
• No auto-pause
• Use your music app normally

Configuration

1. Open the app on Karoo 3
2. Enable/Disable the service
3. Choose mode: Dynamic or Normal
4. Adjust settings:
   • Pause Threshold: Speed below which music pauses (default: 0.5 km/h)
   • Min Volume: Volume when stopped (Dynamic mode)
   • Max Volume: Volume at high speed (Dynamic mode)
   • Default Volume: Fixed volume (Normal mode)

How It Works

Speed Detection

Uses Karoo's built-in sensors:

• ANT+ Speed sensor
• BLE Speed sensor
• GPS speed (fallback)

Music Control

• Monitors MediaSession (Spotify, YouTube Music, etc.)
• Sends pause/play commands automatically
• Adjusts system volume

Compatibility

• ✅ Karoo 3 (Primary target)
• ✅ Android 8.0+ (for testing on phones)
• ✅ Spotify, YouTube Music, Apple Music, etc.
• ✅ Any Bluetooth headphones

Troubleshooting

App doesn't detect speed

• Check if speed sensor is connected in Karoo
• Try riding for a few seconds first
• GPS must be active

Music doesn't pause

• Enable service in app
• Check Dynamic Mode is active
• Ensure music app is playing

Volume not adjusting

• Check app has permission to modify system settings
• Try Normal Mode first to test basic functionality

Development

Project Structure

karoo-dynamic-headphones/
├── app/src/main/java/com/lenne0815/karooheadphones/
│   ├── MainActivity.kt              # UI and settings
│   ├── KarooHeadphonesApp.kt        # Application class
│   └── service/
│       └── DynamicHeadphonesService.kt  # Core logic
├── app/src/main/res/
│   └── layout/activity_main.xml     # UI layout
└── build.gradle                     # Dependencies

Karoo SDK

Uses hammerheadnav/karoo-ext for:

• Speed data streaming
• Sensor integration
• Extension lifecycle

Changelog

v0.1 (2025-02-20)

• Initial release
• Dynamic volume based on speed
• Auto-pause when stopped
• Configurable pause threshold
• Mode switching (Dynamic/Normal)

License

MIT License

Credits

• Karoo SDK by Hammerhead
• Built for Karoo 3 cycling computers