CarOS Profile Switcher

A Magisk module for Android that automatically switches device profiles based on Android Auto connection state (wired/wireless) and intelligently manages device resources for in-car use.

🚗 Features

Automatic Profile Switching

• WIRED Mode: Activated when USB is connected AND Android Auto is running
• WIRELESS Mode: Activated when Bluetooth is connected to your car AND Android Auto is running
• IDLE Mode: Activated when not in car (battery saving mode)

Intelligent Resource Management

• WiFi Control: Keep WiFi on/off in wired/idle modes (useful for VW Polo 6 compatibility)
• Mobile Data Management: Automatically enable/disable mobile data based on mode
• Bluetooth Control: Smart BT management in wired mode
• CPU Throttling: Limit CPU frequency when idle to save battery
• Charge Limiting: Reduce fast charging in wired mode to prevent overheating
• Battery Saver: Automatically enable when not in car
• Nova Launcher: Set as default launcher automatically
• 🔔 Auto Permissions: Automatically grants notification and location permissions to Android Auto, Waze, Google Maps, and Nova Launcher
• 🎵 Audio Streaming: Stream audio from another device to car speakers via Bluetooth A2DP sink or WiFi hotspot

Configuration

• User-configurable via /sdcard/CarOS/config.env
• Supports multiple car Bluetooth names (regex patterns)
• MAC address matching support
• Verbose logging for troubleshooting
• 📚 See EXAMPLES.md for car-specific configurations

📋 Requirements

• Android device with root access
• Magisk v20.4 or higher
• Android Auto app installed
• Optional: Nova Launcher (for launcher switching feature)

🔧 Installation

1. Download the latest release ZIP from the rel/ directory or [releases page]
2. Open Magisk Manager
3. Go to Modules → Install from storage
4. Select the downloaded ZIP file
5. Reboot your device

⚙️ Configuration

After installation, edit the configuration file at /sdcard/CarOS/config.env:

💡 Quick Start: See EXAMPLES.md for ready-to-use configurations for Audi, VW, BMW, Mercedes, and more!

# Car Bluetooth name(s) - supports regex (e.g., "Audi|VW|Volkswagen")
AUDI_BT_NAMES="Audi"

# Optional: Match by MAC address instead
AUDI_BT_MAC=""

# Wired mode: Keep Bluetooth on (1) or off (0)
ALLOW_BT_IN_WIRED=1

# Mobile data management
DATA_OFF_OUTSIDE=1        # Disable data when idle
KEEP_DATA_IN_CAR=1        # Keep data on in car (for Waze/Spotify)

# CPU throttling when idle (in kHz, e.g., 1516800 = ~1.5 GHz)
IDLE_MAX_CPU_FREQ=""

# Limit fast charging in wired mode (reduces heat)
LIMIT_QUICK_CHARGE_WIRED=1

# Set Nova Launcher as default
SET_NOVA_DEFAULT=1

# WiFi management
KEEP_WIFI_IN_WIRED=1      # Keep WiFi on in wired mode (VW Polo 6, etc.)
KEEP_WIFI_IN_IDLE=1       # Keep WiFi on when idle

# Automatic permission management
AUTO_GRANT_PERMISSIONS=1  # Auto-grant notifications & location to AA, Waze, Maps

# Audio streaming options (choose one or both based on what works for your setup)
ENABLE_BT_AUDIO_SINK=0     # Bluetooth A2DP sink (may not work if BT used for car audio)
ENABLE_WIFI_AUDIO_HOTSPOT=0  # WiFi hotspot for audio streaming (alternative to BT)

# WiFi hotspot settings (if using WiFi audio streaming)
WIFI_AUDIO_HOTSPOT_SSID="CarOS-Audio"
WIFI_AUDIO_HOTSPOT_PASSWORD="caros123"

# Verbose logging
VERBOSE=1

🎵 Audio Streaming Feature

Stream audio from another phone to your car speakers via Bluetooth or WiFi. Two methods available:

Method 1: Bluetooth A2DP Sink

When enabled (ENABLE_BT_AUDIO_SINK=1), your CarOS device can receive audio from another phone via Bluetooth.

Limitation: May not work if Bluetooth is already used for car audio/calls (even in wired mode).

How to use:

1. Enable in config: ENABLE_BT_AUDIO_SINK=1
2. Connect your CarOS phone to car via USB
3. On the emitting phone:
   • Go to Bluetooth settings
   • Find and pair with your CarOS device
   • Connect and play music

Method 2: WiFi Hotspot (Recommended Alternative)

When enabled (ENABLE_WIFI_AUDIO_HOTSPOT=1), your CarOS device creates a WiFi hotspot that other devices can connect to for streaming audio.

Advantages:

• ✓ Works even if Bluetooth is used for car audio
• ✓ Higher quality audio streaming
• ✓ Can work in WIRED mode when WiFi is not used by the car

How to use:

1. Enable in config:

   ENABLE_WIFI_AUDIO_HOTSPOT=1
   WIFI_AUDIO_HOTSPOT_SSID="CarOS-Audio"
   WIFI_AUDIO_HOTSPOT_PASSWORD="caros123"

2. Connect your CarOS phone to car via USB
3. On the emitting phone:
   • Connect to the WiFi hotspot (SSID: CarOS-Audio)
   • Use an audio streaming app (e.g., SoundWire, AudioRelay, etc.)
   • Stream audio to CarOS device

Use Cases

• Stream music from a passenger's phone to your car speakers
• Multiple people can share music during the drive
• Alternative to passing phone cables around

Important Notes

• Both methods work in WIRED mode only (USB connection to car)
• Does NOT work in WIRELESS mode (both Bluetooth and WiFi may be used by car)
• Automatically disabled when IDLE to save battery
• WiFi hotspot method requires an audio streaming app on the emitting phone
• Bluetooth method may not work on all devices (A2DP sink support required)

📝 How It Works

1. Boot: The module starts automatically via service.sh
2. Permissions: Automatically grants notification and location permissions to critical apps (Android Auto, Waze, Google Maps, Nova Launcher)
3. Monitoring: Every 3 seconds, the module checks:
   • USB connection status
   • Bluetooth connection to configured car device
   • Android Auto process state
4. Profile Application: When state changes, applies appropriate profile:

Profile Details

Profile	WiFi	Bluetooth	Mobile Data	CPU	Battery Saver	Charging
WIRED	Configurable	Configurable	Configurable	Max	Off	Limited*
WIRELESS	On	On	Configurable	Max	Off	Normal
IDLE	Configurable	N/A	Off*	Limited*	On	Normal

*Configurable via config file

📦 Building a New Release

Quick Build (PowerShell)

# Set version number
$VERSION = "0.2.4"

# Create release directory if it doesn't exist
New-Item -ItemType Directory -Force -Path "rel"

# Create the ZIP file (from project root)
Compress-Archive -Path "caros_config.sh", "module.prop", "post-fs-data.sh", "service.sh", "system.prop", "grant_permissions.sh", "META-INF" -DestinationPath "rel/CarOS_Profile_Switcher-v$VERSION.zip" -Force

Write-Host "Release created: rel/CarOS_Profile_Switcher-v$VERSION.zip"

Manual Build Steps

1. Update Version Numbers:

   # Edit module.prop
   version=0.2.4
   versionCode=5  # Increment by 1
   description=... # Update changelog

2. Update Service Script Version:

   # Edit service.sh (around line 257)
   log "CarOS Profile Switcher service v0.2.4 started"

3. Create ZIP Archive: Include these files/directories:

   • caros_config.sh
   • module.prop
   • post-fs-data.sh
   • service.sh
   • system.prop
   • grant_permissions.sh
   • META-INF/ (entire directory)

4. Name Convention:

   CarOS_Profile_Switcher-v{VERSION}.zip
   

   Example: CarOS_Profile_Switcher-v0.2.4.zip

5. Save to Release Directory:

   # Move to rel/ directory
   Move-Item "CarOS_Profile_Switcher-v0.2.4.zip" "rel/"

Using Git Bash (Alternative)

#!/bin/bash
VERSION="0.2.4"
mkdir -p rel
zip -r "rel/CarOS_Profile_Switcher-v${VERSION}.zip" \
    caros_config.sh \
    module.prop \
    post-fs-data.sh \
    service.sh \
    system.prop \
    grant_permissions.sh \
    META-INF
echo "Release created: rel/CarOS_Profile_Switcher-v${VERSION}.zip"

🐛 Troubleshooting

💡 Tip: Check the FAQ.md for common issues and solutions!

Check Logs

View module logs:

adb shell cat /data/adb/modules/caros-switcher/log.txt

Check Current State

adb shell cat /data/adb/modules/caros-switcher/state.json

Common Issues

Module not working:

• Ensure Magisk is properly installed
• Check that Android Auto is installed
• Verify Bluetooth name in config matches your car

Bluetooth not detected:

• Enable verbose logging (VERBOSE=1)
• Check logs for Bluetooth dump
• Try using MAC address instead of name

WiFi/Data not switching:

• Some Android versions have restricted APIs
• Check logs for error messages
• May require additional permissions/SELinux changes

📄 Files Structure

caros-profile-switcher/
├── build.ps1                # PowerShell build script
├── build.sh                 # Bash build script
├── caros_config.sh          # Central configuration defaults
├── grant_permissions.sh     # Automatic permission management
├── module.prop              # Magisk module metadata
├── post-fs-data.sh          # Early boot initialization
├── service.sh               # Main service loop
├── system.prop              # System property overrides
├── README.md                # This file
├── CHANGELOG.md             # Version history
├── CONTRIBUTING.md          # Developer guide
├── EXAMPLES.md              # Configuration examples
├── LICENSE                  # MIT License
├── .gitignore               # Git ignore rules
├── META-INF/                # Magisk installer
│   └── com/google/android/
│       ├── update-binary    # Installation script
│       └── updater-script   # Magisk marker
└── rel/                     # Release builds (not in repo)

🔄 Version History

• v0.2.3: WiFi smart management + VW Polo 6 compatible + bug fixes
• v0.2.2: Nova Launcher default setting
• v0.2.1: Configuration fixes
• v0.2.0: Initial release with profile switching

See CHANGELOG.md for detailed version history.

📚 Documentation

• README.md - Main documentation (you are here)
• EXAMPLES.md - Car-specific configuration examples
• FAQ.md - Frequently asked questions
• CONTRIBUTING.md - Developer guide
• CHANGELOG.md - Version history

📜 License

This project is licensed under the MIT License - see the LICENSE file for details.

👤 Authors

• Vincent Airiau - GitHub

🙏 Acknowledgments

• Magisk community for the module framework
• Android Auto developers

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Note: This module requires root access and modifies system behavior. Use at your own risk. Always test in a safe environment first.