I'm surfing the web for hardware ideas and came across this forum. Thanks! It has been helpful.
In reading the messages I found some posts that indicated issues with sirens, so I thought I'd mention something I've seen that might address some of their problems. This idea is from a guy I used to work with. He owned the company that installed sophisticated fire and security systems for businesses and their corporate executives. Some of his clients lived on hundreds of acres and were a mile or more away from the nearest neighbor. Outdoor sirens went unnoticed and daylight burglaries were easy to pull off before the sheriff could arrive. Knowing this my friend redesigned his systems. Instead of simply notifying everyone about the burglary, he actively protected the valuables with indoors sirens. He located 140 dB sirens (yes, 140) in the ceiling above the jewelry safe, gun safe, cedar safe, dining room (heirloom silver), home theater, garage, and at every computer. The sirens warbled at a frequency and pitch that made it very difficult to concentrate on anything requiring detailed manual dexterity. Even if you were wearing mouse-ear ear protection, the vibrations penetrate the skull through the bone. After moving the sirens indoors the rural burglaries stopped.
I am designing a similar system but with 120 dB sirens. I think the 140s were a little bit of overkill. If you knew the exact warble you could probably get away with 95 dB sirens.