In late 2023, the Libre Space Foundation asked my company to develop an Open Source photometer—a device designed to help astronomers measure and understand sky quality. The goal was to create a community-friendly tool accessible to enthusiasts and professionals alike, with an ambitious vision of building a global, crowdsourced network of photometers. While the network is a story for another time, this talk focuses on the journey of designing and deploying the device itself.

After writing down the requirements, we realized that the architecture—comprising I2C sensors, a microcontroller, and WiFi connectivity—was relatively straightforward. This simplicity gave us the opportunity to explore new technologies. In particular, could we use Rust to build a robust, unattended, battery-powered device?

Fast forward to today: we have manufactured several hundred units and are collaborating with the Instituto de Astrofísica de Canarias, a leading research institute, to rigorously test the devices under challenging conditions. In this session, we’ll share the lessons learned during development, the hurdles we overcame, and how Rust has since become an integral part of our workflow.