How to see an enemy if they breach your area.

[Skvez]

Most cameras can see IR, remote controls look 'pink' on all three of my cameras.
IR is a range of light not a single frequency, most military prefer to work up towards the Short Wave IR these days rather than the 'just not quite Red anymore IR'.

There is also a big difference between being able to see the LED and being able to see things near the LED from the light reflected light back off the object. (You can see a car headlights when the car is still a mile away but the car driver can't see you until you're a lot closer).
If you point a single LED towards you, you can see which alarm was set off but you need a pretty big array if you want to be able to illuminate what set it off and where they are moving to. I also don't like the idea of needing a camera to see out the window at night, needing it to hand and needing it to have good batteries. Also the display on the camera is going to backlight your face a lot in the otherwise pitch darkness.

In a SHTF scenario the smell of excrement will become a lot more common and something people will become somewhat habituated to. I don't think a bucket of it will be as effective as some suggest here. Many people without toilet paper will adopt "one hand to feed with and one hand to wipe with".