Here’s a great article I thought you would like:

Another thing I noticed recently when I was at Lowes was that in the electronics area, they sell piece by piece security systems. You can buy the control unit, a foghorn type alarm, door sensors, windows sensors, and so on. Buy only the pieces you need.

And like ADT and other systems, they are completely wireless. How cool is that?

The door sensor was only about  $12. The rest of them vary in price, but that is a whole lot cheaper than a guardian system I saw for $700.00.

Have a great 4th of July.