When Internet Fails,
Your Phone Saves Lives
A peer-to-peer mesh network that turns every smartphone into a rescue beacon.
Even if you don't need rescue, hold out your phone so SOS messages can pass through.
Built for Natural Disasters
When infrastructure fails, communication is critical. AnchorMesh keeps you connected.
Three-Level Alert System
Simple, clear status codes that rescuers can prioritize instantly.
User cannot edit messages - only status options
Red
Critical
Life-threatening emergency requiring immediate rescue
Yellow
Injured
Medical attention needed but not immediately life-threatening
Green
Safe
No assistance needed - acting as a relay node
How Mesh Networking Works
Everyone becomes a node in a life-saving network. Your phone is a bridge.
Internet Fails
App detects when connection to the outside world is lost after multiple ping failures.
Smart Detection: Ping Google 3 times. If all fail, activate mesh mode.
Mesh Activates
Your phone automatically switches to BLE mesh networking mode.
Bluetooth Low Energy: 100-400m range in open air
SOS Broadcast
Trapped victims broadcast their status and GPS coordinates.
Packet: UUID | GPS | Status | Timestamp (17-20 bytes)
Epidemic Routing
Nearby phones silently relay messages through the mesh network.
Store-and-Forward: Every phone carries every message
Cloud Sync
When any phone regains internet, all stored SOS messages upload automatically.
Acknowledgment system prevents infinite propagation
Posts SOS with GPS coordinates. Broadcasts signal continuously.
Receives aggregated SOS data. Dispatches rescue teams to locations.
Technical Deep Dive
Built with precision engineering for reliability when it matters most.
BLE Specifications
Packet Structure
| Bytes | Field | Size |
|---|---|---|
| 0-1 | App Header | 2B |
| 2-5 | User ID | 4B |
| 6-7 | Sequence | 2B |
| 8-15 | GPS (Lat/Lon) | 8B |
| 16 | Status Code | 1B |
| 17-20 | Timestamp | 4B |
Total: ~21 bytes per SOS packet - fits in any BLE MTU
GPS Optimization
Coordinates stored as 32-bit integers (10^7 multiplier) for optimal precision-to-size ratio.
DEFCON Battery System
Smart power management based on threat level detection.
API check every 30 min. BLE/GPS OFF.
Earthquake/Hurricane detected. Ping Google to verify.
All systems active. Continuous broadcast.
Platform Support
Cross-platform compatibility with platform-specific optimizations.
Android
Background Features
- Google Nearby Connections (100m range)
- WorkManager for background tasks
- Programmatic MTU control
- Battery optimization bypass
iOS
Device Support (iPhone 6+)
- - Low Power Mode detection only (cannot override)
- - Background UUID overflow area
- - System-managed MTU
- - 30-second wake limit from silent push
- - Scan + Broadcast simultaneously in background
- - State Preservation & Restoration
- - Silent push for disaster alerts
Offline Utilities
Essential tools that work without any network connection.
Offline Map
Pre-cached maps for navigation
Compass
Digital compass for direction
GPS Tracker
Real-time location tracking
SOS Strobe
Visual signal for rescuers
Ultrasonic SOS
17-20kHz inaudible beacon
Medical Info
Blood type, allergies, etc.
Offline Wiki
Emergency survival guides
Community Chat
Mesh-based local messaging
Ultrasonic SOS Technology
Converts SOS data to inaudible sound waves (17-20kHz) that can be detected by nearby phones, even without Bluetooth connectivity.
Hot or Cold Proximity
Guide rescuers to victims using signal strength and sensor fusion.
RSSI Distance Calculation
N = Environmental factor
Direction Finding (LocBLE)
Without Bluetooth 5.1+ hardware arrays, we use sensor fusion with the phone's compass and gyroscope.
User spins 360° while app records RSSI at each heading.
Strongest signal indicates direction to target.
