As far as Geiger counter kits go, I did a bit of trawling around before settling on one.
If memory serves, my criteria ended up going something like this:
- Affordable (for me this meant < $100 USD)
- Open Source
- Bring Your Own Tube (I have the one from my dad)
Searching on the web led to several kits of varying documentation and quality. One in particular stood out to me:
(Note that this is also sold by AdaFruit.)
I very nearly bought this one, and it is a wonderfully straightforward design. One of the most amazingly human and connective things MightyOhm does is to acknowledge a source of inspiration for the design: DIYGeiger.
When I followed that lead, I found a much more sophisticated set of kits that are under active development by person with passion for the projects and a predilection for documentation.
When I was a kid, i wanted a box that clicked around radiation, allowing me to peer into the unseen world of nuclear physics. MightyOhm's kits do just that.
DIYGeiger's kits add to that the worlds of WiFi connectivity, signal analysis, colorful GUIs, useful DC input ranges, SD card logging, microcontroller programming, and GPS tracking. Source code is available and documentation doesn't stop with 'put 1/8W 1Kohm resistor in slot R5'--it goes on to talk about power supply selection, schematics, and instructions for tweaking the high voltage along with background information about making HV measurements and characterizing GM tubes. On top of that, the kits did not necessarily come with a GM tube and were adjustable to work with whatever tube is available.
I went with the GK Plus (with Display Adapter), Pololu regulator, and GK WiFi Kit. I think I'll add a GPS module eventually. Note that at this point I had not really settled on a power source beyond using a battery. I got the Pololu as a matter of flexibililty.
BroHogan's customer service was responsive and helpful when I had a problem with the shipping address, and he threw in a couple of amazing little freebies that I expect to put to good use.