This project measures the background radiation outside the house, and transmits it to a display station inside the house. The outside sensing unit is solar powered (but it doesn’t have to be), and should have a range of at least 50m. The display station inside the house continuously displays the current background, and logs it to an SD card (along with date / time, temperature and other data). Daily high counts and other information are also displayed.
The Outside Sensing Unit
With the UC_PWR jumper on the Geiger Kit removed. This separates the Vcc that powers the Geiger HV circuit from the ATmega328. This allows the sketch to control the power to the Geiger circuit from an I/O pin. Using the Geiger circuit only when needed saves power.
I designed a small yellow board that plugs into the Geiger Kit that holds the RFM22B transceiver. A 3.3V voltage regulator is also provided as the “load” output of the solar charger is unregulated. (click pic for larger image)
For more detail: Wireless Monitoring Geiger Station