October 30, 2025
Click wars: tone vs. terror
Modifying a radiation meter for (radioactive) rock collecting
DIY Geiger glow-up sparks safety squabbles and geek applause
TLDR: A hobbyist added a small computer to a vintage radiation meter to turn clicks into a tone that rises with radiation and filters background, making rock hunting easier. Comments cheer Ludlum’s repair-friendly design but argue about safety and “clicks vs. tones,” with jokes about Geiger ASMR and Fallout cosplay.
Radioactive rock hunters just got a wild upgrade: Maurycy’s vintage Ludlum Model 3 radiation meter now hums like a treasure detector after a tiny computer turns noisy clicks into a tone that rises with activity and subtracts background buzz. In simple terms: old-school clacker becomes a smart beeper, so you can look where you’re walking. The crowd went immediately split. One camp cheered the hack as pure maker magic, while another clutched pearls over modding safety gear. The star comment? fastneutron swooned over Ludlum’s repair-friendly ethos, praising the company for open schematics and even helping a teen fix ancient gear.
And then the memes arrived. “Geiger-click ASMR” trended, with jokes about Fallout cosplay and IRL Minecraft ore hunting. Analog purists grumbled that the classic click is sacred; tinkerers clapped back that a tone plus background subtraction is more usable in the field. Safety nags worried about high voltage and “don’t tape a brain into a Geiger box,” while pragmatists quipped, “The real risk is tripping while staring at the dial.” The vibe: retro meter meets modern brain, and the community is fighting over whether you should listen to the clicks, the tone, or just your common sense. Read the full saga on Maurycy’s blog.
Key Points
- •The article modifies a Ludlum Model 3 meter by replacing its audio section with a microcontroller that subtracts background and outputs an audible tone proportional to net count rate.
- •Geiger tubes are good for alpha/beta surface detection but poor for locating specimens; scintillation counters detect gamma well but have high background that makes audio clicks unusable.
- •Event signal is tapped from pin 3 of the CD4093BE; a 22k resistor protects the microcontroller due to higher voltage levels on that IC.
- •A UPDI programmer can be improvised using a USB–UART adapter with a 1k resistor; Atmel ICE may need a firmware update to avoid initialization errors.
- •Physical installation requires insulating and securing the microcontroller and keeping wiring away from high-voltage sections to prevent arcing and damage.