# MeshCore SAR: Off-Grid Communication for Search & Rescue Operations When the grid goes down, lives are on the line. MeshCore SAR is a revolutionary mobile application that enables search and rescue teams to communicate, coordinate, and share critical information—even when cellular networks and internet connectivity are completely unavailable. Built on cutting-edge mesh networking technology, MeshCore SAR transforms ordinary smartphones into powerful off-grid communication devices using low-power radio hardware. Whether you're coordinating a wilderness rescue, managing a disaster response, or operating in remote areas, MeshCore SAR keeps your team connected when it matters most. ## Why MeshCore SAR? Traditional communication systems fail when you need them most: - **Cellular networks** collapse during disasters or don't exist in remote wilderness - **Satellite phones** are expensive and have limited messaging capabilities - **Radio systems** require licensing and lack modern features like GPS integration MeshCore SAR solves these problems by creating a resilient, self-healing mesh network that: - ✅ **Works completely off-grid** - No cellular, WiFi, or internet required - ✅ **Extends range through mesh routing** - Messages hop through nearby devices - ✅ **Integrates GPS tracking** - Real-time location sharing on offline maps - ✅ **Specializes in SAR operations** - Purpose-built features for emergency response - ✅ **Uses affordable hardware** - Low-cost LoRa radios via Bluetooth --- ## 🗨️ Messages: Reliable Communication When Networks Fail [*Image placeholder: Messages screen showing conversation with delivery status*] At the heart of MeshCore SAR is a robust messaging system designed for mission-critical communication. ### Key Features: **🎯 Multiple Communication Modes** - **Direct Messages**: Private one-to-one communication with team members - **Public Channel**: Broadcast updates to all nearby devices - **Rooms**: Persistent message storage for coordination centers **📡 Smart Message Delivery** - **Intelligent routing**: Messages automatically find the best path through the mesh network - **Delivery confirmation**: Know when your message reaches its destination with ACK tracking - **Automatic retries**: Failed messages retry automatically with progressive timeouts - **Flood fallback**: Critical messages use broadcast mode if routing fails **🚨 SAR Marker Messages** Send location-tagged alerts with a simple message format: - **🧑 Found Person**: `S:🧑:37.7749,-122.4194:Survivor located, needs medical attention` - **🔥 Fire Location**: `S:🔥:40.7128,-74.0060:Wildfire spreading rapidly northeast` - **🏕️ Staging Area**: `S:🏕️:34.0522,-118.2437:Base camp established with supplies` These special messages automatically appear as markers on the map, making critical information instantly visual for the entire team. **📊 Message Status Tracking** Every message shows its delivery status: - ⏳ **Sending** - Message is being transmitted - ✅ **Sent** - Message queued with expected acknowledgment - ✔️✔️ **Delivered** - Confirmation received with round-trip time - 🔄 **Retrying** - Automatic retry in progress - ❌ **Failed** - Delivery unsuccessful after all attempts **🌍 Multilingual Support** Full localization in English, Croatian (Hrvatski), and Slovenian (Slovenščina) ensures teams can communicate in their native language. --- ## 👥 Contacts: Know Your Team's Status and Location [*Image placeholder: Contacts list showing team members with GPS locations and battery levels*] MeshCore SAR's contact system goes beyond simple names and numbers—it provides real-time situational awareness for your entire team. ### Contact Intelligence: **📍 Real-Time Location Tracking** - GPS coordinates automatically broadcast at configurable intervals - Location history tracking (last 100 positions per contact) - Distance and bearing calculations from your position - "Last seen" timestamps for situational awareness **🔋 Battery Monitoring** - Battery percentage displayed for each team member - Voltage telemetry via Cayenne LPP format - Early warning when team members need to conserve power **🛤️ Mesh Network Routing** The app shows routing information for each contact: - **Direct (0 hops)**: Connected directly to your radio - **Good path (1-2 hops)**: Reliable routing through 1-2 intermediate devices - **Medium/Long path (3-5+ hops)**: Extended range through multiple hops - **No path (flood mode)**: Messages broadcast to entire network **👔 Role-Based Identification** - Add emoji prefixes to names (🧑🏻‍🚒 for firefighter, 👮 for police, 🏥 for medical) - Instant visual identification on map and in contact lists - Customizable display names **📡 Contact Types** - **Chat** (Team Members): Standard team members shown on map - **Repeater**: Network infrastructure nodes that extend range - **Room**: Message servers with persistent storage and login capabilities **📞 Contact Sharing** - Export contacts as business cards - Share contacts directly over the mesh network - Import contacts from other team members --- ## 🗺️ Map: Offline Navigation and Tactical Awareness [*Image placeholder: Map screen showing team members, SAR markers, and offline terrain*] The map is where everything comes together—combining team locations, SAR events, and offline navigation into a single, comprehensive tactical display. ### Map Features: **🗺️ Offline Vector Maps** - **MBTiles format**: Lightweight vector maps that work completely offline - **Multiple layers**: Street maps (OpenStreetMap), topographic (OpenTopoMap), satellite imagery (ESRI) - **High zoom levels**: Street-level detail up to zoom level 19 - **Smart caching**: Tiles cached locally for 30 days **📍 Team Member Tracking** Each team member appears on the map with: - Blue circle markers with role emoji - Battery level badge (green/yellow/red indicators) - Distance from your location - Tap to view detailed information and message directly **🚨 SAR Event Markers** Critical events appear as color-coded markers: - 🟢 **Green** - Found Person - 🔴 **Red** - Fire Location - 🔵 **Blue** - Staging Area - 🟣 **Purple** - Object - Time elapsed since report - Tap to navigate and view details **✏️ Map Drawing Tools** Collaborative tactical planning: - **Line drawings**: Sketch routes, boundaries, or directions - **Rectangle areas**: Mark zones, perimeters, or sectors - **8 color palette**: Red, blue, green, yellow, orange, purple, pink, cyan - **Share drawings**: Send to channel or specific rooms via mesh network - **Collaborative editing**: All team members see drawings in real-time - **Ultra-compact format**: Efficient JSON encoding reduces bandwidth usage by 37% **🧭 Detailed Compass Dialog** Ultra-compact location display: - Current GPS coordinates - Toggle between Decimal Degrees (DD) and Degrees/Minutes/Seconds (DMS) - Tap outside to close (no buttons needed) - Perfect for quick location checks **📡 User Location Tracking** - Blue pulsing circle shows your current position - Navigation icon for direction - Tap to center and track your movement - Configurable accuracy settings **📊 Map Legend** Collapsible legend in top-right corner: - Team member count - SAR marker count by type - Quick reference for marker colors **🎯 Smart Navigation** - Tap any SAR marker in messages to navigate on map - Automatic tab switching - Map centers and zooms to selected location - Clears navigation after viewing --- ## 🔧 Technical Innovation ### Mesh Network Protocol - **MeshCore Protocol**: Open-source, battle-tested mesh networking - **LoRa Radio**: Long-range, low-power wireless technology - **BLE Connection**: Smartphone connects to companion radio via Bluetooth - **Intelligent routing**: Self-healing paths through the network - **Flood mode fallback**: Guaranteed delivery for critical messages ### Smart Features - **Adaptive location broadcasting**: Only sends updates when you move significantly - **Progressive retry logic**: Failed messages retry with increasing timeouts - **Cayenne LPP telemetry**: Standardized sensor data format - **Contact synchronization**: Automatic contact list updates - **Message persistence**: Rooms store messages for later retrieval ### Built for Reliability - **Provider-based architecture**: Efficient state management - **Automatic reconnection**: Handles radio disconnections gracefully - **Message queue management**: Synchronizes messages in order - **Battery optimization**: Configurable tracking intervals - **Memory management**: Automatic history cleanup --- ## 🌟 Real-World Applications **Search & Rescue Operations** - Wilderness rescue coordination - Missing person searches - Cave rescue operations - Mountain rescue teams **Disaster Response** - Hurricane and flood response - Earthquake emergency communication - Infrastructure failure scenarios - Mass casualty incidents **Remote Operations** - Forestry operations - Mining site communication - Border patrol and security - Wildlife management **Training & Exercises** - Team coordination drills - Radio discipline training - Navigation exercises - Emergency preparedness --- ## 🚀 Getting Started MeshCore SAR works with affordable LoRa companion radios that connect to your smartphone via Bluetooth. The app handles all the complexity—you just: 1. **Connect** your radio via Bluetooth 2. **Add contacts** to your team 3. **Start messaging** and tracking locations 4. **Download maps** for your area 5. **Coordinate** your mission No cellular service. No internet. No limits. --- ## 🌍 Open Source & Community-Driven MeshCore SAR is built on the open-source MeshCore protocol, fostering a community of developers and users who contribute to its continuous improvement. Whether you're a first responder, amateur radio enthusiast, or outdoor adventurer, you're part of a global network working to keep people connected when it matters most. --- ## 💡 The Future of Off-Grid Communication In a world increasingly dependent on fragile infrastructure, MeshCore SAR represents a paradigm shift: resilient, decentralized communication that works when everything else fails. As climate change drives more frequent disasters and teams operate in increasingly remote locations, mesh networking isn't just an alternative—it's essential. **MeshCore SAR isn't just an app. It's a lifeline.** --- *MeshCore SAR is compatible with iOS 13+ and Android API 21+. Requires compatible LoRa companion radio hardware.* **Repository**: [github.com/meshcore-dev/meshcore.js](https://github.com/meshcore-dev/meshcore.js) --- ## 📸 Screenshots *[Placeholder sections for images]* ### Messages *Screenshot showing conversation with delivery status, SAR marker messages, and message options* ### Contacts *Screenshot showing contact list with GPS locations, battery levels, and routing information* ### Map - Team View *Screenshot showing map with multiple team members, distance indicators, and user location* ### Map - SAR Markers *Screenshot showing map with various SAR markers (person, fire, staging area) and color coding* ### Map - Drawing Tools *Screenshot showing map with line and rectangle drawings, color palette, and toolbar* ### Map - Offline Layers *Screenshot showing different map layers (street, topographic, satellite) selection* ### Settings *Screenshot showing connection status, radio parameters, and location tracking settings* ### Contact Details *Screenshot showing detailed contact information, telemetry data, and message history* --- **Ready to experience off-grid communication?** Connect your radio and join the mesh network today.