LIA: an open-source Meshtastic GPS tracker for your pet's collar

LIA, by Jose Garcia Aguado (JGAguado), is an off-grid LoRa tracker built to clip onto a pet's collar. Instead of a cellular GPS tag with a subscription, it is a Meshtastic node: a custom KiCad board with an ESP32-S3-MINI-1, a Wio-SX1262 LoRa module, a u-blox SAM-M10Q GNSS receiver (GPS, Galileo, GLONASS and BeiDou), a MAX17048 battery gauge, a TP4056 charger and an LSM6DSOX motion sensor. A three-position switch picks the mode. HIGH is a beacon for active searching: the LED stays on and it sends its position every 30 seconds. LOW is the everyday tracker: it wakes about once a minute, tries for a GPS fix (giving up after 90 seconds), sends it and goes back to deep sleep. OFF cuts power to the MCU while still letting the battery charge. Positions and command replies go as direct messages to one target node whose ID is set in the firmware at build time, so you need a second Meshtastic node (or a phone paired to one) to receive them; you can also DM the tracker commands such as GPS, BATTERY, LED ON/OFF and HELP. There are two hardware versions running the same lia_v1 firmware: V1.0 with an 18650 cell (3,500 mAh; the docs estimate about 4 hours in beacon mode and about 3.3 days in tracker mode) and V1.1 with a 50 x 37 x 4 mm 1,000 mAh pouch cell for a smaller case. Three enclosures (V1.0 detachable, V1.0 fixed, V1.1 fixed) come as STEP/STL files for 3D printing or CNC. The board is meant to be ordered as a turnkey PCB assembly (the author suggests Seeed Fusion) from the Gerbers, BOM and pick-and-place files in the repo. Firmware is stock Meshtastic plus a LIA board overlay, built with PlatformIO (a PowerShell script automates it); the Meshtastic web flasher does not support it. Charging is over USB-C or a magnetic 4-pin pogo cable like the one for Seeed's T1000. Still a prototype: the first boards needed a rework because the IMU's I2C lines were crossed. Licensed CC BY-NC-SA 4.0, so personal and community builds are fine but commercial use needs permission. Set the LoRa region for your country before transmitting.