With all the interest of radioactive particles reaching western shores from the failed reactors in Japan, I decided to get out my geiger counter that I made over 20 years ago. Readings from my counter can be shared with the world in real time with Ustream. Ustream is a website that allows you to make your own Live broadcasting channel for free. All that is needed is a fast and reliable internet connection. Here is my Ustream Channel showing the geiger counter in action. On the right of the geiger counter is the interface and a LM317 based power supply for 5 volts. The power supply is common enough and info on this is not shown.
Step 1: The Geiger Counter
I built my geiger counter 20 years ago from scratch. I incorporated a optocoupler as the output. Every time a particle is detected, a pulse is made and the counts can be monitored by a PC. A search on the internet will show you how to make your own or you can get a kit or finished product. What is needed is an output that can drive an optocoupler.
Step 2: Free Counter Software
To monitor the counter you need software that will count and log the readings. I always welcome free software if it is good and useful. A search on the internet found a program called "Digital Geiger Counter" from Images Scientific Instruments. The program will log and plot the data in real time. The software is not a demo and is not limited. The company also provide counters and kits for those who don't want to build from scratch like I did.
Step 3: The Interface
To get the counts to the software, an interface is needed. This interface (PDF) will count pulses during each 1 sec intervals and pass them along to the software through the PC serial port. I connected my Acer netbook with a Airlink 101 USB dongle to the RS232 output of the interface. The interface converts count per second to 9600 baud serial with a Picaxe microcontroller. The program is only a few lines of code and is shown on the drawing. You can get a Picaxe at Sparkfun and the free complier at Revolution Education.
The interface can be built on a piece of perfboard. I made some PC boards for use with the picaxe and used one of them.
Step 4: Streaming at Ustream
To start broadcasting you need to get a free account at Ustream. Livestream is another site that allows live streaming. I believe Ustream is the most popular. You can use Ustream's program called Producer to stream your desktop image of Digital Geiger Counter. The other alternative is to use the online application to do the streaming and use another free produce called Manycam to broadcast your desktop image of Digital Geiger Counter. I found broadcasting runs faster with Google Chrome instead of Firefox. That may be just with my Acer, just give it a try.
Step 5: My Ustream Channel
I have my geiger counter running on-line at Ustream. There you can see in real-time the levels of background radiation. My station may or may not be on 24/7. I like to use my Acer Aspire One for other things besides streaming.
Below is a screen shot at my Ustream channel.