On Wednesday, 27 September 2017 14:57:50 UTC+1, wrote:

When I re-furb'ed my last house I fitted window switches to all
accessible windows and external doors, so didn't need to bother with
PIRs. The current house already has a "professionally installed" alarm
with PIRs and door contacts, but no window contacts.
I was going to replace the PIRs with (a large quantity of) window
switches but am having second thoughts because of the unsightly wiring.

SWMBO is concerned about staying with the PIRs because, if we set the
downstairs ones at night, of what happens if someone goes down for a
drink or a wander around in the night. How does everyone else cope with
this?

I'm wondering whether it's viable to set-up an external boundary around
the house using infra red or laser beams/detectors (above animal
height). Has anyone used this technique?

Window switches: Enamelled copper wire can be disappeared in a superficial scratch in plaster. Make sure to fit them to part of the frame where distortion & wind can't trigger them. Check the current is in range for the reed relay, they tend to fail if it's too high or too low. They don't of course detect broken glass. You can get glass break detectors too.

PIR: they will sense you if you go there. Full stop.

Beam break: used that long ago, very effective. Can sometimes be placed where you won't walk at night, and where any door shutting will trigger it. Make sure the detector & mirror can't ever slip out of alignment or it'll trigger.

Personally I'd want to treat one detection event as a minor warning, and 2 as a person present rather than 1.


NT