On Wed, 30 May 2012 00:07:25 +0100, Adam Aglionby
wrote:

John`s relay logic is clever but CJ suggested Quad PIR in about post
4, which is what a quad PIR does

http://www.future-mag.com/0710/071032.asp

mebbe we are the google groups users ;-)

it showed up OK I just didn't get what he was on about in post 4 ;)

Dennis has a good point about PIRs not seeing through glass, or
acrylic or polycarbonate, no matter how thin it blocks the PIR, only
thing found that was IR transparent was polythene and going by CJ
presumably PET plastic.

Have an ancient Motorola Homesight setup , PIR operated cams , usb
hub, cams were meant to be indoor use only, thought would mount in
floodlight housings, they do, but not with the glass on...

Ended up sealing obvious seams with silicone and mounting cams in
flood housings with no glass, now lasted over 4 years through 2 severe
winters with snow piled on them, floodlight housing is good cam mount,
had to point out to other regular users of area that cams were there ,
becomes part of the scenery.

They caught fuzzy images of last 2 intruders, enough to give cops
exact time and relative size and build of hoodies involved that and
individual bolt croppers apparently leave a dsitinctive unique cut,
probably out of the young offenders now.

After that upgraded to DVR and more cams (and more locks), including
one in door viewer for that close up. Avtech DVR`s are cheap and have
phone apps for remote viewing,

Though DVR has all the motion detection whingdings use the old moto
for checking to see if need anything more detailed from the DVR.

indeed my (naturally) "cheapo but worko fineo" older HDD recorder based
CCTV system does a similar job recording constantly, I use the IP cams to
alert me to any (more) incidents that deserve scrutiny, saving hours of
possibly pointless footage review.

Wired current cams with CAT5 baluns specifically with power, video and
audio, not interested in audio but leaves a spare pair for wiring PIR
to alarm inputs on DVR.

Most PIRs seem to be 2 part case and lens, after way Motos have stood
up to driving rain and snow for years reckon 12V interior PIR with a
smidge of silicone should last OK, at the current cost annual
replacement would be fine.

Yup that seems a good way to begin experiments.

If its a deterrent or they face on to publicly accesible areas warning
signs are a necessity.

necessary for what? ....in practical terms?

Cheers
Jim K