Scott Powell has posted full instructions for building a compact GPS tracker which communicates over the Ripple LoRa mesh network — and has proven its efficacy in the field by strapping it to his dog.
"These tracker modules use the Semtech LoRa radios and compatible Arduino dev boards," Powell explains of his project. "Initially, there is just support for the Adafruit Feather, but will be more added over time. The modules can be used to track the location of anything remotely, via the LoRa packet radio mesh network."
Powell's instructions are based around an Adafruit Feather with LoRa radio module, a BN-180 GPS receiver, a 900MHz flexible dipole antenna, and a lithium-polymer battery — though the latter component comes with a warning for anyone following his recommended supplier. "The wires must be swapped in the connector of these Lipo batteries before plugging into the Feather," Powell notes. "That is, this battery has right connector type, but the polarity is reversed!"
The tracker, assembled into a 3D-printed housing, communicates via the Ripple LoRa mesh network and can be managed through the Ripple Commander mobile app. "This is the main UI of the app, where you can chat with other 'pager' users in the network (who use the Ripple Messenger app), plus monitor your special nodes, like repeaters and the GPS Tracker nodes," Powell says. "Tap on a tracker node in the list, and you should see the device status screen (see second screen-shot above). Tap on the tracking option 'LIVE TRACK', and you should then be able to monitor the live location of the module."
The tracker builds on an earlier project to add LoRa mesh communication capabilities to a smartphone for use outside normal cellular network coverage areas, which could be assembled using either an Adafruit Feather M0 RFM95 development board or the TTGO ESP32 LoRa with OLED board.
Full build instructions are available on Powell's project page.