As I announced to my newsletter subscribers, I knew I was going to be busier than usual participating in the Meshtastic Build-Off 2026 competition. Rather than leaving the blog without new posts in the meantime, and because I think this can be a genuinely interesting series, I decided to write about parts of this process so you can follow along with the development of a device from PCB to firmware integration. Though in this case, the firmware side will be a bit different from the usual, since the goal is to get my new hardware running with Meshtastic's existing firmware.The device I'm building is called the RetroMeshDevice. The idea was to build a companion node that is as minimal as possible and doesn't…