My GPS logging, geiger counter.
It all started when I saw sparkfun was selling this very easy to use geiger counter. It was using a really nice LND tube.
The LND tube is the same tube that is in the gamma scouts that I have seen in the past. The tube is receptive to Alpha, beta, gamma, and x-ray radiation. They are also built very consistently.
They can be picked up here:
So, I ordered one. I also ordered a few other sparkfun things to go with it.
I got a openlogger: http://www.sparkfun.com/products/9530
I wanted to use cells out of a reused laptop battery, and I wanted to run the whole device at 5 volts. So, I ordered this great little board that sparkfun makes that gives me a dc-to-dc converter, a battery charger, and a microusb charging connector. The board is great:
I then modeled rough designs of all of the parts in solidworks and smashed them into a assembly. The assembly looks great, here it is:
The assembly gave me the ability to design plastics to house everything. I could go to techshop and laser cut acrylic for the project.
I cut the box up, then used acrylic cement to cement it all together.
Here is the end result:
Action shot of it counting ionizing particles in New York:
For those interested, I'll describe how the program functions. The arduino program is constructed of two sections. The setup and the loop section. The setup section is pretty straight forward. It sets up all of the serial ports, initializes all of the software serial ports, and send commands to the gps receiver to turn off all of it's normal output. It's not needed. The loop section then listens for output from the geiger counter. When output is received, there is some parsing that happens. The parsing is looking for a new, valid count from the geiger counter. When a count is detected, it adds the output to a circular buffer that is the counts per minute buffer. Then, I send a GPGGA query to the GPS. This makes the GPS respond with a GPGGA sentence. I store that sentence in a memory buffer. After the gps data is in the buffer, I read the current info from all of the onboard sensors on the geiger counter. I then format the gpgga sentence to a new sentence with all of the new, yummy data and output it. Source! Here is the Arduino sketch for the project. It's not pretty. Please do not hate. http://wordpress.michaelgregg.com/projects/geiger-counter/geiger_counter.pde Here are all of my solidworks models and drawings for this project. http://wordpress.michaelgregg.com/projects/geiger-counter/geiger-counter-solidworks.tar.gz All of this code is opened under the GPL license.