LoRa Rangefinder

Ben Oliveau and John Cole Lomax

A board that uses GPS and LoRa to present an auditory indicator of distance to other boards.


We wanted to use the LoRa protocol to transmit GPS data across distance, with an audio output corresponding to the distance of two modules. Our project uses a M20050 GPS module, and transmits over LoRa through a COM18085 module, with orchestration handled by an ESP-32. A speaker (along with an audio amp) serves as an output for the distance between two communicating units. The board is powered by a 9v rechargable battery, stepped down to 3.3v.


The board dimensions are 2.3" by 3.6". We used a large amount of copper pour and stitching for conductivity and thermal protection.

We learned how big components really were! We found that ICs were prone to being shorted to ground, and that components with a large thermal mass (e.g. big inductors) can be challenging to solder.

Challenges:

  • Layout vs. Assembly

  • What looks good in a layout isn't always so easy in assembly.

  • When in doubt, debug first.

  • We had way more debugging at the end than if we had started debugging each subsystem separately.

  • Via, via, via

  • We had to use vias for grounding, for thermals. They were incredibly important, and we realized that the more current you are moving, the more of them you need.