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A scope for installing PIR?

Discussion in 'Security Alarms' started by John O, Apr 11, 2005.

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  1. John O

    John O Guest

    I need some help from you pros. I'm staring at an assessment question that
    says something like this: "when installing a motion sensor in an odd-shaped
    room, scope the perimeter and eliminate obstructions."

    I'm assuming there is a device that I would look through that gives me some
    idea of what the PIR would see. But I can't sniff out anything on the web to
    clarify this. I've given this a good try, and far too much time, but I can't
    find a link to such a device. Does anyone know where I'd find one?

    -John O
  2. Chuck Norris

    Chuck Norris Guest

    close one eye and don't move your head is a approximation of what your
    PIR will 'see', unless your have a 'hallway lens' on it.
  3. John O

    John O Guest

    I need some help from you pros. I'm staring at an assessment question
    Now that's what I would do, too. At one time I had a pretty good eye for
    selecting the proper lens for my Canon A-1. But, does someone sell a 'scope
    a room' tool?

    -John O
  4. R.H.Campbell

    R.H.Campbell Guest

    Sir, there is no such device to my knowledge. Far more likely this is simply
    a poorly worded statement that is trying to tell you go around the room and
    make note of obstructions that would prevent the device from fully "seeing"
    the room or area you are trying to cover.

    Ideally, locate the motion on an interior wall that is also looking inwards
    and away from heating vents, and streaming sunlight coming in from windows.
    Follow the manufacturers recommendations to the letter, and it might also be
    wise to set the device to the least sensitive setting, assuming your device
    will allow for. You generally don't want motions set too sensitively, since
    the poor ones anyway, can false alarm due to certain environmental

    Think of a motion like a glass of water, full completely, with the meniscus
    in a positive mode. If you literally breathe on the motion, it will spill
    water (ie: alarm). With the better motions,or motions set to a less
    sensitive setting, think of them as that same glass of water, but with the
    meniscus in a negative mode. They will handle a little nudge without
    spilling water (ie: tripping the alarm). However, any real presence of a
    warm body is like smashing the glass with a hammer....

    Home Security Metal Products
    Ottawa, Ontario, Canada
  5. Chuck Norris

    Chuck Norris Guest

    been having knee problems?
    I need a doctor to tell me what that means ;)
  6. John O

    John O Guest

    Sir, there is no such device to my knowledge. Far more likely this is
    That is entirely possible (the poorly worded part). Interestingly, I'm told
    this phrase appears in a certification exam offered by one of the major
    vendor-neutral organizations. Looks like I may retain my faith that I can
    search down *anything* on the Internet. LOL

    Thanks for the explanation.

    -John O
  7. R.H.Campbell

    R.H.Campbell Guest

    Hehe...yeah, I thought that might be the wrong spelling. But your get my
    drift I'm sure....:))

  8. R.H.Campbell

    R.H.Campbell Guest

    You're welcome. Feel free to post any other security related questions you
    have. There are a multitude of professionals on this group with the full
    breadth of scope of all matters relating to security. There will always be
    someone who can give you an intelligent answer (right or wrong....:)))

    Home Security Metal Products
    Ottawa, Ontario, Canada
  9. It comes with a left handed dike and a skyhook.

  10. Jim

    Jim Guest

    I'd think that this means the same thing as if someone told you to go
    to a job site and "scope out" the job. Meaning, go take a look and see
    what needs to be done. You wouldn't take a "job scope" to do this and
    neither would you need a "PIR scope" to see if a motion detector would
    work in any given area.
  11. Jim

    Jim Guest

    If I close one eye, I see dark.

    I've tried contact lenses but never "hallway" lenses.
  12. John O

    John O Guest

    I think you are right. It's too bad that jargon like this made it into this

    -John O
  13. John O

    John O Guest

    Most PIRs have a built in test meter. It is called a walk test LED.
    Good point. I used to work down the hall from the guys that designed all the
    Heath/Zenith stuff sold in the home stores, and those lights were on a few
    of the better PIRs. ( I have tons of that stuff in my garage) Most just use
    the lights to which they are normally attached, but the process is the same.

    -John O
  14. I need some help from you pros. I'm staring at
    Not really. Just use your eye. Stand where the PIR will be mounted and
    look for obstructions. Each PIR model has its own unique pattern of "fields
    of view" (FOV's). After using a few you will become accustomed to their
    characteristics. For now, check the coverage pattern in the installation
    instructions as a guide.

    Remember to verify that the detector is installed at the correct height as
    specified in the manual. If it's too high you may miss nearby areas. If
    it's too low the area of coverage will be reduced. Also, if you are using
    "pet resistant" detectors, note that most of these require very careful
    placement to avoid false alarms.

    When designing a system note that it's usually unnecessary to cover every
    square foot of the protected premises. Protect the places where a thief is
    likely to move about, especially corridors, access to stairs (not usually
    the stairs themselves though) and important target locations like the master
    bedroom and family room if it's a residence.


    Robert L Bass

    Bass Home Electronics
    2291 Pine View Circle
    Sarasota · Florida · 34231
    877-722-8900 Sales & Tech Support
  15. I think, if I remember correctly, Sentrol used to sell this giant clip on mirror you were supposed to clip on the detector body while mounted and you could "see" the coverage area. Good idea, but totally impractical---since your head was usually in the way of the mirror...I think I used it twice.
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