I don't think it so much the infrared as the lack of a photocell in
some of the units. I have a few with no photocell, and they behave as
you say yours does. I've pulled them down and use them in my shop to
keep me from killing my self when I go in there at night. They still
suck, but in the shop, it really doesn't matter. Get a good premium
motion sensor and it will do the job. I have one in my carport that is
just great, it comes on at night and lights things up when I drive in
or even let the dog out.