In this project the Raspberry Pi with the PiCam is used as a wireless camera which can transmit images over long distances, usually hundreds of meters! Images are transmitted by amateur radio (ham radio) using slow scan television (SSTV) on the 2 meter band (144.5MHz).
Thanks to Oliver Mattos and Oskar Weigl the Pi can generate the high-frequency FM signal itself — no additional electronics are needed for low-power transmissions. For a little bit more power, a one or two transistor amplifier would be suitable. Furthermore a low pass filter is recommended to filter out higher harmonics of the signal.
This project also contains a Python script which detects movement. Using this script, the Raspberry Pi can be used as a wireless security cam at distances far outside the range of normal WiFi networks. Be aware that you need a ham-radio license to use this application!
Credits to KI4MCW (SSTV), Oliver Mattos and Oskar Weigl (PiFm).