Looks like another project...
Lets see, I looked on fleabay at security systems, seems most are wireless. I have gone through countless cordless phones over the years, I have determined that batteries are an issue, at least they have been in the past.
I have some wireless sensors. The batteries last well over a year, so I change them all every year along with my smoke detector batteries. 9V batteries are not an issue. The issue with a wireless sensor is the alarm panel checks the sensors every so often to see if they are still there. If you leave, say, a window open without a 2nd magnet in the open position, the panel checks the sensor and finds it open. After several hours of this, say sleeping with the window open, the panel determines a sensor is bad and reports it. You then have to correct the situation before you can set the alarm. This means closing the window and pushing a relink button to tell the panel the sensor is O.K. This situation is eliminated with a 2nd magnet in the open position.
I would loke to forget how many times in the summer the windows were open and rain came in, I can imagine what a wireless window sensor would do when wet...
Wireless sensors are usually mounted on the side of the window at the center of the window and a wire connects to the magnet(s). Rain will not come in and blow around to the side and up to the center of the window. If it is raining that bad, you will have more to worry about than a twenty dollar sensor.
I bought a set of driveway alerts today from Home Depot, I have 2 bird houses on trees that have no residents currently, they are naturals for the PIR detectors. The receiver has a 9V battery and an ac wall wart adaptor. It also provides a contact relay for input into a security system.
Hope you like to sleep at night.
Outdoor PIR detectors tend to flake out more than anything I have ever dealt with regarding home security. If you adjust it for a man-sized object when it is warm and dry outside you will get different results when it is cold and damp and vice versa. Someone walks down your driveway. BING! A deer walks down your driveway. BING! A pack of raccoons walks down your driveway. BING! You get the idea.
Indoor PIRs work really well for us in areas where there are no animals moving about. For example, in our first house we had a small unfinished basement. One PIR in the corner covered the stairs coming down from the back door and all of the basement windows. One fifty dollar sensor for 8 windows and a stairwell. Very efficient and only one wire to run, too. So think about using them in those types of areas, like a garage, barn, etc... although one hangar at the airport kept getting set off at night by an owl!
Lights need to be added, have fixtures for outside of barn.
We have some inexpensive X10 floodlights with PIRs. They are flaky about distinguishing animals from people as I said, but they have a neat feature in that I can set them so that if one goes off it will trigger all of the rest of them. So if someone comes around the back side of the house and sets off the back motion sensor, it tells all of the other floodlights around the other sides of the house to turn on as well. 360 degree lighting around the entire house. No place for bad guy to hide except away from the house.
