Project

MeshCore SAR

Off-grid LoRa coordination for search and rescue

MeshCore SAR is a communication layer for search and rescue teams working beyond cellular coverage. Paired with MeshCore radios, it gives a team messaging, GPS positioning, and offline tactical mapping when the usual infrastructure is gone.

Source on GitHub Read the write-up

At a glance

Transport: LoRa mesh
Link: Bluetooth
Maps: MBTiles, offline
Needs: MeshCore radios

Features

Works without cellular service or internet access
Long-range, multi-hop transport over MeshCore LoRa radios
Live location, bearing, and distance for every contact
Offline vector maps with field drawing tools
Geo-tagged SAR markers such as Found Person, Fire Location, Staging Area, and Object Found
Direct messages, shared channels, and persistent rooms
Battery telemetry for teammates in the field
Compass pointing toward contacts and markers
Role badges so team roles are visible at a glance
Automatic relaying through the mesh

Hardware requirements

MeshCore SAR needs MeshCore devices for LoRa transport. The app connects to those radios over Bluetooth and turns a smartphone into a field terminal for coordination and navigation.

It works with dedicated MeshCore nodes built for field deployment, repeaters that are already installed, other team members' client devices, and room nodes acting as persistent hubs. Because it uses the same devices, a team can extend an existing MeshCore network or set up a new one without changing how it operates.

Communication

Messages come in four forms: private one-to-one messages, public channels for network-wide updates, rooms that keep a shared log such as General or Emergency, and SAR marker messages, which are geo-tagged alerts with delivery tracking.

Tactical display

Offline vector maps (MBTiles) with street, topo, and satellite layers. SAR event markers are color-coded by incident type. Drawing tools cover routes, search zones, and quick annotations, and the compass gives direction and range to people, nodes, and markers.

Client device improvements

The client-side work targets reliability in the field and clearer information at a glance:

Localized interfaces, including Slovenian and Croatian
Watchdog timer that recovers automatically from software freezes
NRF52 hardware watchdog, which reduces the risk of device lockups
Redesigned device screens with simpler navigation and cleaner layouts
GPS display showing both fix age and accuracy

Also