fitting a pir near roadside

multimick · Jan 16, 2019

got a job fitting a pir near side of road (4 metres away) to contol 2 led floods any tips to avoid cars or pushbikes setting it off ,i can point it down and buy one with sensitivity control but any other tips please

Rpa07 · Jan 16, 2019

The timeguard make, gives opaque stickers that you use to shield that aspect of the PIR sensor - you should be able to do the same if picking up motion below the light and around. Might have to do walk test a few times to get it right.

Midwest · Jan 16, 2019

Install a decent quality PIR.

The Ghost · Jan 16, 2019

@Richard Burns yes I can see that now you say it. Lucky I am retired now then.

Ray Pooley · Jan 16, 2019

multimick said:
got a job fitting a pir near side of road (4 metres away) to contol 2 led floods any tips to avoid cars or pushbikes setting it off ,i can point it down and buy one with sensitivity control but any other tips please

PIRs detect heat not motion. At least that's the case with alarm systems that I've worked on. You should be able to adjust the range to its minimum and point them down. Just need to work it out.

Richard Burns · Jan 16, 2019

Generally a PIR sensor has the top half as long range and the bottom half as short range so blocking off long range should help. I often use good quality waterproof tape to block sections if not using the ones Rpa07 mentions.

ipf · Jan 16, 2019

Ray Pooley said:
PIRs detect heat not motion. At least that's the case with alarm systems that I've worked on. You should be able to adjust the range to its minimum and point them down. Just need to work it out.

PIR motion detectors detect the movement of heat...….hence they are motion detectors. In other words, detecting both. Stand perfectly still and no operation.

Ray Pooley · Jan 16, 2019

ipf said:
PIR motion detectors detect the movement of heat...….hence they are motion detectors. In other words, detecting both. Stand perfectly still and no operation.

Yes. That's true. If the heat source happens to be moving. But the fact that the heat source might be moving is irrelevant. If the moving object is at ambient temperature then a basic PIR won't detect it. They are heat sensors. For example, if someone throws a rock through a window a standard PIR won't detect it. That's why Honeywell, for example, provide Dual Tec sensors. They use both passive infra red, to detect heat sources, and microwave technology to detect moving objects that don't have a heat fingerprint.

buzzlightyear · Jan 17, 2019

Try and get a pir with a high or low sensitivity..,will do the trick .

ipf · Jan 17, 2019

Ray Pooley said:
Yes. That's true. If the heat source happens to be moving. But the fact that the heat source might be moving is irrelevant. If the moving object is at ambient temperature then a basic PIR won't detect it. They are heat sensors. For example, if someone throws a rock through a window a standard PIR won't detect it. That's why Honeywell, for example, provide Dual Tec sensors. They use both passive infra red, to detect heat sources, and microwave technology to detect moving objects that don't have a heat fingerprint.

What's all that got to do with it?
A PIR motion sensor takes a moving heat source to operate.

Midwest · Jan 17, 2019

My neighbours PIR detects my leafless tree, swaying in the wind

Ray Pooley · Jan 17, 2019

ipf said:
What's all that got to do with it?
A PIR motion sensor takes a moving heat source to operate.

I know it's off topic but just clarifying my first comment which you challenged. Here is a picture of a brick. It was thrown through a window. The PIR is just above my head when I took this picture. It did not trigger and it was functional. I tested it afterwards. I replaced all PIRs with Dual Tec.

[ElectriciansForums.net] fitting a pir near roadside

ipf · Jan 17, 2019

It would've triggered if they'd jumped through the window after smashing it, though.....

Midwest · Jan 17, 2019

ipf said:
It would've triggered if they'd jumped through the window after smashing it, though.....

Perhaps it was just criminal damage.

ipf · Jan 17, 2019

Midwest said:
Perhaps it was just criminal damage.

No doubt, it was.

fitting a pir near roadside

multimick

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Rpa07

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Midwest

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The Ghost

Ray Pooley

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Richard Burns

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ipf

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Ray Pooley

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buzzlightyear

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ipf

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Midwest

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Ray Pooley

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ipf

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Midwest

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ipf

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