The Rad-O-Matic Is a “Retro” Radiation Meter

Hans Jørgen Grimstad often swaps parts with a friend after being a bit too overzealous with “late night shopping sprees on AliExpress.” In this case he was given a LilyGo T5 ePaper display, meant as a digital price tag. However, with an ESP32 microcontroller and SD card support, it’s capable of so much more.

Initial programming of the device — dubbed the "Rad-O-Matic" — was fairly easy, based on example code found on GitHub. After getting things working, he decided to hook up an RD200M radon sensor to make it into something useful. This took a little tinkering, but he was eventually able to get it to reveal radon levels on-screen.

From there, the project needed an enclosure, which was designed in Fusion 360 and printed, and finished to resemble a weathered/found artifact. This involved scratching up the filler and paint to make it look like it’d been finished, then worn down over years of use and perhaps even neglect.

The LilyGo T5 was set up to show an indicator needle, which graphically moves along radiation levels as a sort of period appropriate gauge. A cracked fresnel lens rounds out its retro aesthetics, and the Rad-O-Matic now monitors radon levels in “the basement lab" at somewhere around “128 Becquerel /m3 on an autumn day.”