Re: PIR Defeat, What To Use?

["coord" <splunge@xxxxxxxxxxx>]

"Stanley Barthfarkle" <sbarth@xxxxxxxxx> wrote in message
news:2UvHg.2852$yO7.87@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> "Jen...tel" <poleclimber@xxxxxxxxx> wrote in message
> news:1156477581.255051.286570@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>>
>> Alex Threlfall wrote:
>>> Note that they only defeated a simple PIR, not a Microwave PIR :) Also
>>> they moved very fast accross the room,
>>
>> Ah, good point didn't realize that.  But can we really get installed
>> only microwave units? I thought, they were both IR and MW.  If that's
>> so, don't you still need the IR to activate along with the MW to get an
>> alarm? If they defeated the IR by preventing it from seeing the IR
>> given off by a person, even if the MW actvated, wouldn't it still not
>> go into alarm because there will never be an IR detection?   I'm not in
>> the alarm business so I may be way off base and confusing myself.
>> Thanks.
>
>
>
> Combination Microwave/PIR motion sensors, known as "Dual-Tech" motion sensors, are set so that
> each technology is more sensitive, but requiring both to trip to activ ate the relay.
>
> BTW- if they "defeated" a PIR by moving through a room very quickly, the PIR wasn't set up
> properly to begin with. Proper placement, aiming angle, and sensitivity adjustment are all
> vital elements of good catch performance, while reducing the possibility of false alarms.
>
> A good alarm system consists of "layers" of protection, and not just a single motion sensor for
> the interior protection.

This is the segment referred to and dates...

http://dsc.discovery.com/tvlistings/episode.jsp?episode=57&cpi=25032&gid=0&channel=DSC

BTW...watch to see what happens when they walk through holding up a large white sheet.....