Project Marathon

Project Marathon started out as an effort to build a long range radio project that would transmit data or even pictures over long distances. In the end it just ended up being a test of LoRa's capabilities, where I just tested signal strengths and successful transmissions at various distances.

This project page will detail the setup and the tests done.

Setup

Raspberry Pi Pico

The Pico was used in this project because it's cool and new. But also because when running MicroPython, the Pico can act as a easy to use terminal to interact with circuits or chips. In this case, the Pico's SPI capability allowed for control of the RFM95W. Essentially, if you define functions in the main.py file you upload to the Pico, you can trigger complicated actions with over the REPL terminal.

REPL is actually the key to all of this and it basically makes the Pico act like a Python terminal when plugged into a computer. In short, I only really wanted to control the RFM95W and the Pico offered the easiest interface to do this.

RFM95W - LoRa Module

I went with this module because I own two of them and they offer the best range from the modules I could find. (If there is a better module I missed, let me know somehow.) I attached a quarter wavelength antenna to each RFM95W with -3 dBi.