In Flexion: Wireless long range motion detectors - TractorByNet.com

I'd like your input / advice for helping secure my farm equipment. My barn, no doors, 3 metal gates, is located approximately 300 feet from my house. I'd like to install a "unauthorized" person detector, via motion or infrared whatever, at the barn that would send a signal to the house and turn on an alarm siren of some sort. I've found a system that I think would work but would like to know if an ...Flexion