The purpose of the project is to build Geiger counter radiation sensor add-on board for Arduino that can be used to detect and measures emission of nuclear radiation: alpha particles, beta particles or gamma rays. Libelium, project designer, said that he want to help people to measure by themselves radiation levels instead of trusting in the general advises. User can also use this board along with Arduino to measure ionizing radiation from specific places.
The Geiger counter board has two main parts, the power circuit and the signal circuit. The power part produces high voltage needed by the Geiger tube (400V – 1000V), while the signal circuit is used to adapt the pulses output from the tube and connect it to the input of the microcontroller. Once the tube is powered, microcontroller receives the pulses, count them, and get the value of radiation.
This radiation sensor Arduino shield counts with three different actuators: Speaker, Leds and LCD. The Speaker sounds each time a pulse is generated as it is connected directly to the Geiger tube output producing the typical “chirp”. The piezo speaker will play one audible sound, one “chirp” for each particle counted and the LED will blink also one time for each particle. In addition there is a LED bar (3 green LEDs and 2 red LEDs) which connected to Arduino. This bar can be configured in order to give a visual information of the measured radioactivity amount. The last is a LCD screen where the information of the radiation is shown (counts per minute and µSv/h).
The project has been tested and has been validated using Geiger tubes from LND (US), GStube (Russia) and North Optic Electronic (China). But the board can also be connected with other tube which works inside the range 400V-1000V from other vendors. If you want to build Geiger counter board by yourself, here is the link for schematic and source code. The design of the board is open hardware and the source code is released under GPL.