Maybe not looking as much towards a total DIY project as much as I am finding some parts that will get me fixed up. We are having problems with people in my yard and I need to build an invisible fence type perimeter around my place with some type of basic audible alarm in the house.
I have found simple driveway alarms which are just like the garage door units but I need to pull like a 50-100ft beam across the yard and in a few different places and I would rather not be buying several of these not-cheap sensor units with a stack of receivers in the house.
I am open to links to places to buy this stuff at the right price or thoughts on PCB or bread board build ups to roll my own. If this is not as complex as it sounds, I might like to just build my own for the fun of it I guess. I am not sure of all the parts that are involved in a system like this or even how they work. Is this just an IR transmitter and receiver and when the receiver loses signal, it goes off?
If we go DYI on this, let me know what kind of circuit we would be looking at here. I should note that I have seen some circuits for basic sensor systems but we need to build a wireless system and I have never done anything wireless. Not sure what that is all about. So far, it looks like we basically will just be using an IR LED to produce a beam of IR light, reflect that back with a mirror, then receive that with an IR receiver and when that receiver drops out, the circuit is tripped. It also looks like the IR LEDs are pulsed for some reason I do not understand yet.