A simplex repeater for ham radio using the Raspberry Pi
https://sites.google.com/site/radioetcetera/home/peaterpipyr
TwoToneDetect
TwoToneDetect is Python program that detects two-tone pages, records audio, and sends the recording to email or cell phones. It's free for personal and noncommercial use by public safety agencies and organizations. http://www.twotonedetect.net