wrote

I use an X10 motion detector without any floods. Then when it detects
and sends and x10 signal, the program another box turns on the house
floods on that side of the house, if it's nighttime and sounds a chime
in the house. But, it will not detect a cold car or a car that is at
the ambient air temperature. So, if a car is running a a pretty high
speed and then pops in front of the detector, it probably sees no
difference and ignores it. However, if the car is really warmed up and
approaches slowly, allowing the hood, etc. to warm up, it detects as the
sensor sees a difference between the air temperature and the car.
Because I have a slow very steep road coming to my drive and then about
100' of drive, it usually detects. Although, at Halloween, I actually
put one of these sensors next to the road to fire off a Halloween
animation. It usually saw most cars, however, when I was testing with
my own car, cold out of the garage, it occasionally missed. Another
problem is that when the outside temperature gets to the upper 90s, it
won't detect a person, again because there is little difference between
the body and the ambient. The best way to reliably detect a vehicle
coming onto your driveway is either a pressure sensor or metal mass
detector, or a photo cell across the drive; the former probably won't
detect critters, the latter will if they are tall enough. Sorry for
rambling on.
The only "really good" motion detector I've ever seen is a video
camera with night vision running a pixel change comparator program on
a computer, controlling the lights. You set the percentage change rate
sensitivity on the program, and if, say, 10% of the pixels change over
a 15 second period, it triggers. This allows you to fine tune the
response to either respond or not respond to something the size of a
squirrel, or a racoon, or whatever.

A barn door moving at 1 foot per minute might be able to sneak in
where a running squirrel would be nabbed, depending on how you set it.

X10 has both the cameras and the software, as well as the
controllers, to set up this kind of system.

Again, to be 100% effective, 2 sensors with crossed field of vision
would work better by providing binaural vision

Thanks for the very good information. I am going to be putting a "system"
on my shop as soon as it is finished. I am going to splurge on this, as I
have YET to see a motion detector that either works right, or lasts very
long.

I keep seeing X10 come up, so take it that there are a lot of satisfied
users out there. I just want to get a reliable system that will detect
human bodies, and not animals in the night. I have seen one deer track on
my property in six years. Mainly, I want an intruder alarm for inside a
perimeter, and automatic lights on when it senses something.

I have five metal halides that came off a large hotel in Las Vegas. But
they are 110 stepped up to 220, and take about ten minutes to get bright.
Those will be on a timer for certain hours, and on a switch that I can
regulate. Those puppies make it look like daytime.

Thanks to everyone who made contributions here on this thread. The day
before this thread started, I was thinking of how to word a post about this,
but this has answered all my questions.

Except one. Is X10 the way to go for the money, or is there better that
won't cost an arm and a leg?

Steve