Not long ago, I found myself in the vicinity of the former Trojan Nuclear Power Plant. I say former, because it's not there anymore. The reactor's long gone and the cooling tower was exploded a few years back. I was just under a mile away, and downwind, from the tower when it went down. The cooling tower didn't have exposure to radioactive material when it was in operation, but the dust cloud was still pretty annoying. Interestingly, prior to the nuclear power plant being there, the land was owned by the Trojan Powder Company, maker of explosives. I wonder if the blasting material was made by the Trojan Powder Company. Today, there's just a park and a few abandoned buildings left on the spot.

While I was there recently I pondered the possibility of small amounts of residual radiation in the area. I quickly forgot the thought until I ran across a post by Jeff Keyzer ( about an open source geiger counter he designed.

SMT Geiger Well, who could resist the chance to build a geiger counter and run it around looking for bad stuff at the former sight of a nuclear power plant. Not me. Here at Screaming Circuits, we specialize in surface mount, so I thought it would make sense to re-layout the PCB for SMT components. Which I did. That's the cool thing about open source. (one of the cool things) The design files are accessible.

The only real challenge I had was in finding a few parts substitutions. The exact match wasn't available in SMT for some of the components. Hopefully, I picked good subs. Doing that is frequently not as easy as it might seem. Especially when the original design is not mine so I don't necessarily know which parameters are in the criticle path.

Now I have to get some parts from DigiKey or Element14, PCBs from Sunstone Circuits and I'll have to run over to Eastern Europe to pick up an old Soviet era geiger muller tube. If my layout actually works, I'll pack up the SMT files and BOM and make them available as all open source is supposed to be. If it doesn't work, I'll quietly try to disavow any knowledge of every having tried to mess with it.

Duane Benson

Everybody's building ships and boats

Except us. We're building prototypes.