This post was migrated from a Twitter thread with minor edits. I back-dated it to the original date of publication; first publication on this site in December 2022.
I had a really fun time building the Geiger Counter kit from MightyOhm while at home during pandemic lockdown and explored some neat enhancements.
I added an Adafruit 128x64 graphical OLED display, Particle Argon WiFi microcontroller, LiPo battery pack, and tube voltage monitoring circuit. It features an Analog Devices AD8244 high-input-impedance buffer and a 1 GΩ/3.9 MΩ voltage divider to connect to an ADC pin on the Argon.
I started logging tube voltage, battery voltage, and radiation levels to InfluxDB and noticed something interesting—the tube voltage is highly temperature dependent. Doesn’t seem to affect the radiation measurement though!
I’ve got some ideas to improve the display with a nice graph, and implement a dynamic algorithm to change the integration time automatically based on radiation level, leveraging the horsepower of the Argon.
Oh yeah, and I converted some classic Mac fonts to use with the Adafruit_GFX library—Espy Sans, Chicago, and Geneva—for the ultimate UI bitmap font style.
Michele is a fan of the Chicago version, IIRC. :)