Connecting one light to two PIR detectors?
Discussion
I am pondering fitting a light to illuminate down one side of the house, and would like to use a dusk-to-dawn PIR detector. As far as possible I'd like the PIR detector to cover the whole side of the house, so that the light comes on when you approach from either end.
The problem is that half way along this side of the house is the boiler flue, which sends its exhaust out just above head height. Obviously this will cause a PIR detector to trigger erroneously.
Is it possible to power one light from two PIR detectors? I could mount a PIR detector on each side of the flue, pointing away from it, and this would cover most of the area I want. Would drifting gases still cause a problem?
Can I wire the light in parallel to the outputs of both PIRs, so that it would light up in response to either PIR?
The only problem I can think of is that when just one PIR triggers, the switched output on the other PIR would become live. Would this cause that PIR to malfunction in any way?
The problem is that half way along this side of the house is the boiler flue, which sends its exhaust out just above head height. Obviously this will cause a PIR detector to trigger erroneously.
Is it possible to power one light from two PIR detectors? I could mount a PIR detector on each side of the flue, pointing away from it, and this would cover most of the area I want. Would drifting gases still cause a problem?
Can I wire the light in parallel to the outputs of both PIRs, so that it would light up in response to either PIR?
The only problem I can think of is that when just one PIR triggers, the switched output on the other PIR would become live. Would this cause that PIR to malfunction in any way?
Superb diagram, thanks!
So I just need a length of four-core cable between the PIRs to link the lives, neutrals, earths and switched lives together, then wire my light into one of the PIRs in the normal way. It's obvious when you think about it!
I can see myself needing to glue a piece of opaque plastic to one side of each PIR to act as a "blinker" to stop it seeing any drifting flue gases, but apart from that I think it sounds simple enough.
Thanks for all the help!
So I just need a length of four-core cable between the PIRs to link the lives, neutrals, earths and switched lives together, then wire my light into one of the PIRs in the normal way. It's obvious when you think about it!
I can see myself needing to glue a piece of opaque plastic to one side of each PIR to act as a "blinker" to stop it seeing any drifting flue gases, but apart from that I think it sounds simple enough.
Thanks for all the help!
R1 Indy said:
Yes you can do this no problems.
Here is a very basic diagram I made someone a few years ago
@R1 Indy Sorry to trouble you I'm trying to do the same thing, the diagram you posted isn't showing on here any more presumably as its an old post, I don't suppose you still have it do you?Here is a very basic diagram I made someone a few years ago
Here is my situation.. 
I currently have one motion detected flood light which you can switch off by a switch inside the house, this would be where I took the power from. down the right side of my house is where I keep my motorbike but when I drive in through the gate at night I cant see sh*t so want to have some lights down there. my plan was to have a PIR down there and one where the flood light is currently to switch both of them on. so basically I all lights will come on whether I come in through the gate or step out the back door. Any suggestions?
I currently have one motion detected flood light which you can switch off by a switch inside the house, this would be where I took the power from. down the right side of my house is where I keep my motorbike but when I drive in through the gate at night I cant see sh*t so want to have some lights down there. my plan was to have a PIR down there and one where the flood light is currently to switch both of them on. so basically I all lights will come on whether I come in through the gate or step out the back door. Any suggestions?
Here's the diagram:
I followed it a year ago, works great. We had a single PIR switching on multiple outside lights as you walked up the drive. The problem was it didn't work if you were leaving the house until you were halfway down the drive. I added a second PIR pointing towards our front door on the edge of a front canopy.
I followed it a year ago, works great. We had a single PIR switching on multiple outside lights as you walked up the drive. The problem was it didn't work if you were leaving the house until you were halfway down the drive. I added a second PIR pointing towards our front door on the edge of a front canopy.
I wanted to fit a light to the side of my house where there is a balanced flue and ended up getting one of these which work on a microwave detector rather than PIR. The microwave detector is not triggered by heat. They do 30W & 50W versions as well. The lamp is setup using a small remote control rather than controls underneath the sensor.
I had this exact problem and an eletrical trade place told me to site a remote PIR below the height of the exhaust flue.
This has been sucessful because the hot steam from our condensing boiler naturally goes up. The flue is 110mm from the ground and the PIR is 65mm.
Just been outside to measure it for you its 3 degrees and the boiler was on and emmiting steam. The light didn't come on until I got within range (about 4m) and the PIR is pointing toward the exhaust
Hope this helps
This has been sucessful because the hot steam from our condensing boiler naturally goes up. The flue is 110mm from the ground and the PIR is 65mm.
Just been outside to measure it for you its 3 degrees and the boiler was on and emmiting steam. The light didn't come on until I got within range (about 4m) and the PIR is pointing toward the exhaust
Hope this helps
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