Passive Infra-Red detector triggering too often.

march.brown · Aug 12, 2010

I have an Infra-Red detector pointing down my garden an last night it triggered many times and lit up the garden ... There were no Birds , Dogs , Cats , Foxes or anything else that I could see that could cause the triggering.

I eventually got fed up and checked my garden for any moving tree or shrub branches that might be the culprit ... It was a very calm evening with no movement of foliage ... I eventually got out my Solarforce torch to examine the detector which is about eight or nine feet above ground level ... I found the culprit.

A spider was building a web in front of the sensor and as he (or she) was walking backwards and forwards across the sensor , the 500 Watt light was being switched on ... I relocated the spider (into next doors garden) and I hope that she (it has to be a she) does not cause me any more aggro.

I always thought that the PIR could only be triggered by a warm-blooded animal !

Still the problem is now solved.
.

TooManyGizmos · Aug 12, 2010

~

march.brown ,

As I read your title statement ........
I clicked on it to tell you to look for exactly what you found .

It also happens in homes and businesses with alarm systems . Many false alarms are created by spiders , ants and roaches crawling or flying across the lens of a single P.I.R. detector .

In all the locations I installed alarm systems , I always installed two P.I.R.'s guarding the same area. (each separated by many feet) I connected the two together , wiring the latching "Trigger" contacts in "series" , so that BOTH P.I.R.'s had to see the same intrusion at the same time , (both sending a trigger) before they would send an activation to the alarm panel . That virtually eliminates bugs on just one PIR sending an alarm . Bugs won't be crawling across BOTH detector lenses at the same instant in time .

You might wanna try that wiring approach , if you can . (can you use two P.I.R.'s ? )

( I think I explained that properly --- it's been a long time ago)

I hope you understood what I'm trying to say ?

Anyone having false security alarms should have their alarm tech. wire P.I.R.'s that way.

It's mostly useful in home and business alarms .... I hope it will help ya .

(* P.I.R. = Passive InfraRed Detector) (motion detector , detecting moving body heat)

TMG

~

march.brown · Aug 12, 2010

TooManyGizmos said:
~

march.brown ,

As I read your title statement ........
I clicked on it to tell you to look for exactly what you found .

It also happens in homes and businesses with alarm systems . Many false alarms are created by spiders , ants and roaches crawling or flying across the lens of a single P.I.R. detector .

In all the locations I installed alarm systems , I always installed two P.I.R.'s guarding the same area. (each separated by many feet) I connected the two together , wiring the latching "Trigger" contacts in "series" , so that BOTH P.I.R.'s had to see the same intrusion at the same time , (both sending a trigger) before they would send an activation to the alarm panel . That virtually eliminates bugs on just one PIR sending an alarm . Bugs won't be crawling across BOTH detector lenses at the same instant in time .

You might wanna try that wiring approach , if you can . (can you use two P.I.R.'s ? )

( I think I explained that properly --- it's been a long time ago)

I hope you understood what I'm trying to say ?

Anyone having false security alarms should have their alarm tech. wire P.I.R.'s that way.

It's mostly useful in home and business alarms .... I hope it will help ya .

(* P.I.R. = Passive InfraRed Detector) (motion detector , detecting moving body heat)

TMG

~

Thanks for your reply TMG ... It is only a single PIR outside light , so it isn't giving any call-outs ... I wouldn't bother with a second PIR on this as I don't get too much trouble with this one ... It does let me know when the trees and shrubs need cutting back though.

I always thought that spiders were cold-blooded , which was why I was surprised that this was the cause of the mal-ops.

I might spray some 'Dethlac' round the PIR , just in case the spider walks back from the bottom of next-doors garden ... It works on door threshold strips if any ants or crawlies come into contact with it ... Lasts for months too.
.

march.brown · Aug 12, 2010

march.brown said:
I have an Infra-Red detector pointing down my garden an last night it triggered many times and lit up the garden ... There were no Birds , Dogs , Cats , Foxes or anything else that I could see that could cause the triggering.

I eventually got fed up and checked my garden for any moving tree or shrub branches that might be the culprit ... It was a very calm evening with no movement of foliage ... I eventually got out my Solarforce torch to examine the detector which is about eight or nine feet above ground level ... I found the culprit.

A spider was building a web in front of the sensor and as he (or she) was walking backwards and forwards across the sensor , the 500 Watt light was being switched on ... I relocated the spider (into next doors garden) and I hope that she (it has to be a she) does not cause me any more aggro.

I always thought that the PIR could only be triggered by a warm-blooded animal !

Still the problem is now solved.
.

Well , I suppose you have heard of "Homing Pigeons" but have you heard of "Homing Spiders ?

I took the spider to the bottom of my garden yesterday (evening) and threw it over the hedge into a neighbours garden ... About thirty yards diagonally plus eight feet up a wall to the PIR , I suppose.

Tonight the PIR triggered again and straight away I looked to see if it was that spider weaving her web on the PIR again ... It was.

That spider will never weave again ... It was mortally wounded as it tried to evade capture ... Let's hope that there are no others to take her place.

The only reason that I think that it was a female , is that it was a repetitively annoying animal.
.

TooManyGizmos · Aug 12, 2010

~

Put a dab of red nail polish on the backs of all her babies ........

so you can identify em

~

march.brown · Aug 12, 2010

TooManyGizmos said:
~

Put a dab of red nail polish on the backs of all her babies ........

so you can identify em

~

Better to put a dab of superglue on their feet and they'll stay put !
.

TooManyGizmos · Aug 12, 2010

~

That infra-red detector light is not going to scare off any Birds , Dogs , Cats , Foxes or anything else . It just helps them see better - to find the veggies , beans and fresh chutes .

Turn it off - put a dog pen in the corner of the garden to scare em off.

And there is NOTHIN you can do about birds !

~

PhotonWrangler · Aug 12, 2010

You can try a different fresnel lens in front of the sensor with wider zones molded into it. This should reduce the sensitivity to small objects. Pyroelectric sensors look for 'pulses' of heat as generated when a moving object passes across the boundary from one section of the lens to another one. Wider lenses mean that it takes a larger object to cross a lens boundary to create a pulse.

march.brown · Aug 13, 2010

PhotonWrangler said:
You can try a different fresnel lens in front of the sensor with wider zones molded into it. This should reduce the sensitivity to small objects. Pyroelectric sensors look for 'pulses' of heat as generated when a moving object passes across the boundary from one section of the lens to another one. Wider lenses mean that it takes a larger object to cross a lens boundary to create a pulse.

I'm hoping that with the demise of Mrs Spider , there will be no more problems ... Until another spider takes up residence ... I will just have to spray the PIR with "Dethlac" and see if that solves it.
.

jzmtl · Aug 14, 2010

If it's a good spot for making webs you can count on them. My jeep is a spider magnet with the large spaces in wheelwell, front and back bumper, spare tire, side mirrors etc. I can evict or spray every one on it, and new ones come the next day.

march.brown · Aug 14, 2010

So far , so good !

No mal-ops since the demise of Mrs Spider ... I will get the ladder out and put a spray of "Dethlac" on the PIR soon ... That will last a few months and it is a good reliable contact bug killer.
.

TooManyGizmos · Aug 14, 2010

~

That may work - unless it's a giant web several feet in front of the light and detector .

Then I don't know what you could do .

Consider moving the light ..... maybe ?

You should be using flashlights anyway .
This is a flashlight forum ..... not a P.I.R. Spotlight forum .... Duh :ohgeez:

~

march.brown · Aug 14, 2010

TooManyGizmos said:
You should be using flashlights anyway ... This is a flashlight forum ..... not a P.I.R. Spotlight forum ....

I used my trusty single mode Solarforce L2i (with 18650) to find the culprit , so I'm in the right forum ... It's the spider that was in the wrong place (at the wrong time) ... But not any more ... SPLAT ...

.

Passive Infra-Red detector triggering too often.

march.brown

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TooManyGizmos

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march.brown

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march.brown

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TooManyGizmos

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march.brown

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TooManyGizmos

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PhotonWrangler

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march.brown

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jzmtl

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