Fun with Rust, MQTT, LoRa and Raspiberry Pi

Recently, I was called to give a hand on a small project for fun. It was about tracking groups of people using GPS.

The project was nice and all, problem was trying to get the correct, and simplier, tools for the project.

We found a company that helped us with the hardware stuff and they provide us with some sensors (Dragino LGT-92) and a gateway (Dragino LIG-16). They talk to each other using radio.

The LIG-16 is a gateway that provides a lot of stuff and we used its MQTT client to communicate with our broker (since there was no connection at the location where it was used).

The first idea we tried was to have everything inside a iPhone, but unfortunately we did not found an easy MQTT broker to use internally with the app.

Than, we accepted we need to add an extra device to handle the application. So, we added a Raspiberry PI 4 where we could run the MQTT broker and provide a REST api to be consumed on a offline map on the phone.

This is the application we build:

I wrote a rust application that with rumqtt that provided the borker and client for the MQTT and warp for the web server, and sqlx for the database (no need to orm or anything like, all queries were simple).

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To help with some message decoding I wrote a small library rust_dragino_lgt92_tools