A simple LoRa based device to act as a beacon/pet proximity sensor. Made for my dog Thunder.
The RF96 LoRa radio transmits a packet every ~8 seconds which can be picked up by any nearby receiver. The packet contains the pet's name. It is only a proxyimity sensor, it will not give the exact position of the transmitter.
This is the circuit diagram. The 3V power supply can go up to 3V3 and it can be replaced with a battery or whatever you want.
I have not tested this out but this is a rough estimate of how long the beacon should be able to function on different types of cells.