HackUPC2025 - Vueling

Project: Bluetooth Mesh Messenger
Objective: Create an Android app that enables direct device-to-device messaging via Bluetooth without internet/WiFi, using a peer-to-peer mesh network approach.

Key Components:

1. Bluetooth SPP Protocol

   • Using UUID 00001101-0000-1000-8000-00805F9B34FB
   • Classic Bluetooth for maximum compatibility

2. Core Functionality:

   • Device discovery via Bluetooth scanning
   • Secure socket connections between devices
   • Message relay capability (basic mesh networking)

3. Technical Stack:

   • Android BluetoothAdapter API
   • BroadcastReceiver for device discovery
   • ConnectedThread for socket I/O operations
   • ArrayAdapter for device list UI

Current Status:

• Basic discovery and pairing works
• Connection establishment partially functional
• Message transmission needs debugging

Recent Challenges:

1. Permission handling in BroadcastReceiver
   • Fixed by using MainActivity.this context
2. Discovery reliability issues
   • Implemented proper scan lifecycle management
3. Socket connection stability
   • Added better error handling and retry logic

Immediate Next Steps:

1. Debug message transmission between connected devices
2. Implement message forwarding (mesh capability)
3. Add connection persistence/reconnection logic

Code Context:

• Uses standard Android Bluetooth permissions
• MainActivity handles all Bluetooth operations
• ConnectedThread manages socket communication

Special Considerations:

• Must work without WiFi/internet
• Needs to handle Android 12+ Bluetooth restrictions
• Target API level 31+ compatibility

Requested Assistance:

1. Help debug message transmission issues
2. Suggest improvements for mesh message routing
3. Optimize Bluetooth discovery process

Built With

• android
• kotlin