LoRa GPS lost model finder - the receiver in your hand

thingiverse

Here is the receiver, designed to be fully portable - the handy device. It's primary purpose is to pick up the signal from the model device and provide the full information to the user: where to go and how far from you is the lost model. I need to say that it works really good, tested in the city, among the buildings, with the model in the grass and the receiver in my hand I was able to pick up the signal from a distance of 490m. When there are no bigger buildings in between, the achieved distance was about 700m with the transmitter (model) in the grass on the ground. The reciver is made with the TTGO ESP32 LORA868 board, which features OLED and lipol circuit - very handy. The receiver has its own GPS module, an older separate ublox 8, set with NMEA 115200 baud communication. So the receiver knows where it is, picks up the signal with GPS of the module, calculates the distance and direction to the model, and shows all this information on the OLED - a simple solution. The whole PCB together with the 380mAh lipo is put into printed housing, on top of the housing is also the GPS. Later on I have printed an additional handle, which at the end is glued to the housing - simple. The receiver can be also connected via USB to the power bank, giving many hours of operational time. The receiver does not require any soldering, only connecting of the lipol and the TX signal of the GPS module connected to the pin 25. The GPS shall be configured to work with NMEA and 115.2kbaud - google it how to do this. After flashing using Arduino, it works without a problem if properly made. The informations on OLED are (from top left): - LAT/LON of the model received, - satellites visible by GPS in model, - HDOP of GPS in model, - battery voltage of the model's device, - RSSI of received message from the model, - working time since power up for the unit in the model, - LAT/LON of the receiver (in hands), - satellites of the receiver, - HDOP of the receiver, - time from the last message recived (shall be each 2 minutes), - and within the rectangle: distance to the model and the direction to the model where north is 0 degrees. The transmitter which is mounted onto the model is described here: https://www.thingiverse.com/thing:3466057 Both software works and are already tested - providing a very useful system for tracking the lost model. (Hopefully it will be never used to this :-)) Enjoy at your own risk.