Finally - off the breadboard and into a working environment. It's currently working for 433mhz sensors, I will possibly be adding more frequencies later. For now I will continue refining the code to release it on github.
A few issues. I accidentally flipped the polarities on the siren. I will eventually implement a 12v regulator to up the voltage for the siren for the full 120db power.
My cat set off one of the motion sensors at 6AM, activating the siren. I need to adjust the sensitivity or get pet-friendly motion sensors.