On 27/09/2017 17:24, Andy Burns wrote:
wrote:

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?

You can get dual-beam detectors, which are supposedly spaced so that
animals/birds/trees in the wind etc will only break one beam, but humans
will break both and set them off, then use corner reflectors to bounce
the beam round your perimeter up to 100m, they use pulsed beams
presumably for anti-tamper.

Thanks, I'll look around. It reminds me of that old heist film where the
actress (supposedly) had to learn to gymnastically gyrate around a room
full of IR beams - Entrapment, I think.