External wall lights and PIR

[scooby1]

I am having problems finding an external wall light, the normal type that looks like a carriage lamp or lantern, with it's own integral PIR that allows me to adjust the sensitivity of the PIR. I have one which has adjustments for length of time the lamp is on and also for daylight/dark adjustment but I'm sure I've seen some with an adjustment for sensitivity in addition to those. i.e. to stop the lamp coming on if a leaf or a moth flies by.

TIA for any help on this.

 

[bernardgreen]

Consider using a lamp without an integral PIR and controlled by a separate PIR

Main advantage is that when the lamp fails (or the PIR fails) only one item has to be replaced.

Use this PIR https://www.tlc-direct.co.uk/Products/STIS180B.html and failed PIR is un-likely. Easy to adjust sensitivity and the area it reacts to.

 

[scooby1]

Consider using a lamp without an integral PIR and controlled by a separate PIR

Main advantage is that when the lamp fails (or the PIR fails) only one item has to be replaced.

Use this PIR https://www.tlc-direct.co.uk/Products/STIS180B.html and failed PIR is un-likely. Easy to adjust sensitivity and the area it reacts to.

Thanks for that. I have read some of the technical and installation documents applicable. The PIR appears to work on infra-red heat detection rather than obstacle movement detection. Do all PIRs work on this principle ?

 

[EFLImpudence]

The PIR appears to work on infra-red heat detection

Yes, it stands for Passive Infra-Red.

rather than obstacle movement detection.

Obstacle is a curious choice of word.
They detect variation in Infra-Red caused by movement.

Do all PIRs work on this principle ?

Well, yes, otherwise they wouldn't be PIR detectors.


There are also Micro-Wave motion sensors.

 

[scooby1]

Yes, it stands for Passive Infra-Red.


Obstacle is a curious choice of word. Sorry, should have used "object"
They detect variation in Infra-Red caused by movement. But is it the movement of an object that only has heat ? If so, why do leaves trigger the light ?

Actually I believe I have a light that is faulty. It comes on for no apparent reason during the hours of darkness and I was looking for a sensitivy option to adjust but there isn't one so I was going to replace it with one that has but can't find one.

I have a driveway alarm that triggers a buzzer in the house and that works by motion detection through a beam and not heat detection and I thought that PIR lights worked in the same way.

 

[EFLImpudence]

Actually I believe I have a light that is faulty. It comes on for no apparent reason during the hours of darkness and I was looking for a sensitivy option to adjust but there isn't one so I was going to replace it with one that has but can't find one.

The integral sensors might not have such a function but some of the stand-alone ones do. Adjustable sensitivity.

This one - although I can't find anything stating how it works.
https://www.clasohlson.com/uk/Steinel-IS-1-Motion-Detector/36-2511

 

[bernardgreen]

If there is a warm object behind the leaf then as the leaf moves across the scanned area the leaf will create an IR shadow that the PIR might react to.

 

[scooby1]

The integral sensors might not have such a function but some of the stand-alone ones do. Adjustable sensitivity.

This one - although I can't find anything stating how it works.
https://www.clasohlson.com/uk/Steinel-IS-1-Motion-Detector/36-2511

Thanks for that. I'll investigate.

 

[scooby1]

If there is a warm object behind the leaf then as the leaf moves across the scanned area the leaf will create an IR shadow that the PIR might react to.

I suppose the same applies to moths & bats.

 

[bernardgreen]

although I can't find anything stating how it works.

For a basic lesson in how a PIR works Click HERE

 

[EFLImpudence]

No, I didn't mean that.

I meant there was no information as to what the sensitivity adjustment actually achieved.