New signal wiring -How many ways can PIR's be used in an old home? Need your ideas.

Since wiring is as much about placement as it is about connection techniques it seems fair to put this question in this forum.

I'm excited and experienced in electronics to work with PIR detectors. Most of them have 2 connectors which close

upon activation. They run on 5 to 50 volts (about) some might use 110vac.

A lot purchase of about 30 of them is available to me and I believe for the price of about $67 total is a great opportunity

to learn and get something of value in my home.

At the least I could use them for lighting. At the best they might be useful for security. At least a few are weather resistant.

I need your advice on what the worth of them is for someone who's got a clear idea of what they do but not a clear plan of

all of the things I can do with them. I'd like to incorporate the wiring they need with installation of network wiring.

How about some of your good ideas?

Since wiring is as much about placement as it is about connection techniques it seems fair to put this question in this forum.

If you believe I'm really off base I'll move the thread if everyone agrees it's the wrong place. Thank you