Integrate Meshtastic GPS data to Mobile App via bluetooth
Mobile users on a CalTopo shared map without a cellular connection will not receive positions of other tracked Meshtastic nodes. In this completely offline scenario, only a desktop server receiving serial data from a meshtastic node will be able to populate GPS data of all nodes in the network onto its local offline map.
I am requesting a new feature to add offline meshtastic integration through the mobile app. This way ALL team members carrying a meshtastic node can see each other's position through a shared CalTopo map on their mobile devices while out of cell coverage.
It is very cumbersome to set up a desktop node, especially when it involves adding code and having to verify the serial port assigned each time the node is plugged in. Many users are reporting issues while working through the steps. Mobile integration with Meshtastic devices would allow SAR teams a HUGE advantage.
Comments
10 comments
Yes! This a feature my team is waiting on!
Yes, please do this!
+1
Even if the desktop integration was easier and more reliable, It does require setting that up as a base station so reduces the utility of Caltopo with Meshtastic as an ad hoc network by increasing physical load, taking resources to set it up and slowing response.
This integration would be great!
Could we add to this request integration with APRSdroid? APRSdroid can integrate with BackcountryNavigator, would be awesome to have it integrate with CalTopo instead as the offline mapping is much more robust with CalTopo. APRSdroid has the documentation on their site.
I know we can do APRS with the desktop version, but mobile would allow direct update to my device.
I agree that this sounds like a great potential: CalTopo running on my phone with a Meshtastic node on my backpack... we would have an encrypted team channel for bi-directional sharing of location and messages. Locations/tracks would then be plotted to the map locally. If any of the phones did have internet access, then it would push those new waypoints/tracks to the server as well for the remote Incident Management Team to see them as well.
Yes please on this feature.
While there is an integration that works with the DESKTOP version, there is no version which works with the mobile app over bluetooth. Given the availability of meshastic devices like the T1000E https://meshtastic.org/docs/hardware/devices/seeed-studio/sensecap/card-tracker/ A bluetooth integration with caltopo would provide real-time, no internet needed, team level tracking. This would be a big win for SAR teams.
Also agree - this would be immensely useful in Alaska where we have numerous SAR missions in areas with no cell phone service.
Partial Meshtastic solution for internet-connected scenarios (not true offline mobile)
I’ve been experimenting with building a couple of open-source tools that partially bridge Meshtastic position data into CalTopo for internet-connected scenarios. These do not address the core request here (true offline mobile integration), but may be useful for teams that have at least one connected gateway.
1. Serial/BLE Bridge (GitLab: Meshtastic CalTopo Bridge)
Runs on a local device (laptop, Raspberry Pi, etc.) connected to a Meshtastic node via USB (serial) or Bluetooth BLE. Forwards all heard node positions to CalTopo via the API. Requires internet and CalTopo Teams. Does not use or require CalTopo Desktop.
2. MQTT Bridge (GitLab: Meshtastic MQTT CalTopo Bridge)
Runs on a local device (laptop, Raspberry Pi, etc.) or on a remote server and subscribes to Meshtastic MQTT topics. Field personnel carry only Meshtastic nodes: no phone or internet required. The Incident Command Post, base camp, or any gateway with internet connectivity, receives their mesh broadcasts and relays all received node positions to CalTopo. Multiple gateways can relay the same traffic for coverage; duplicates are automatically filtered. The MQTT broker can be public (mqtt.meshtastic.org) or private, and the locations from your team can be fully encrypted via TLS, Meshtastic Channel Encryption (AES-128/256), and MQTT authentication.
Both of these tools display all heard nodes under Realtime Data → Shared Locations, where you can click to "Record to Map" for the specific nodes you want to track.
Use case: Incident Command Post or base camp with internet access (Wi-Fi, Starlink or cellular) to allow for tracking of field teams carrying Meshtastic nodes.
What this doesn't solve: True offline mobile. Conceptually, this would require CalTopo mobile to act as a Meshtastic BLE client—receiving position packets locally and rendering them similarly to Shared Locations. Until then, I’m not aware of a supported way to feed positions from Meshtastic to CalTopo mobile without the internet (via the API) or a desktop serial connection (CalTopo Desktop).
Happy to compare notes or share lessons learned if it’s helpful.
Hi Dan. That all sounds awesome! I'll have to give this a go soon. Our SAR team recently caved and got Starlink for the command trailer, so perhaps needing an internet connection is fine for now.
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