‘Slave’ light on PIR light

[MyNameIsUrl]

I have an exterior light with PIR, with an additional wire leading from it which powers a second ‘slave’ light within the porch. The additional wire is connected to the switched terminals of the PIR device within the body of the light fitting. I’m replacing the PIR light with a more modern version and there is no access inside the fitting to connect the secondary wire – it’s all sealed including the led lamp.

I’d prefer not to install a second PIR to switch the second light – is there a way I can set up something to sense when the main light is drawing power and use the signal to switch the second light? I have access to both wires inside the house to connect some sort of switching device.

[ReformedCharacter]

I have an exterior light with PIR, with an additional wire leading from it which powers a second ‘slave’ light within the porch. The additional wire is connected to the switched terminals of the PIR device within the body of the light fitting. I’m replacing the PIR light with a more modern version and there is no access inside the fitting to connect the secondary wire – it’s all sealed including the led lamp.

I’d prefer not to install a second PIR to switch the second light – is there a way I can set up something to sense when the main light is drawing power and use the signal to switch the second light? I have access to both wires inside the house to connect some sort of switching device.

There are contactless sensors that will measure AC current, such as:

https://shop.pimoroni.com/search?q=current%20measuring%20sensor

But it depends on how much tinkering you want to do.

RC

[csearle]

I have an exterior light with PIR, with an additional wire leading from it which powers a second ‘slave’ light within the porch. The additional wire is connected to the switched terminals of the PIR device within the body of the light fitting. I’m replacing the PIR light with a more modern version and there is no access inside the fitting to connect the secondary wire – it’s all sealed including the led lamp.

This may be unhelpful, in which case I apologise in advance. If you haven't already chosen the replacement light then there are some modern ones that still provide access to the switched-live that activates the light. I recently installed some of these for example.

Chris

[csearle]

This thing can switch a 0.5A load when a 0.2A current is detected. So if the current of the sensed light is 200mA or more and the light to be switched draws less than 500mA then you could use it. (It would have to be mounted inside an enclosure though to be safe.

Chris

[DrFfybes]

This may be unhelpful, in which case I apologise in advance. If you haven't already chosen the replacement light then there are some modern ones that still provide access to the switched-live that activates the light. I recently installed some of these for example.

Chris

Hi Chris,

are these any good? I was going to ask on here for a good brand of security flood light, having purchased https://www.wickes.co.uk/Luceco-EFLD20B ... /p/205574# last year. I thought being metal bodied it might be slightly better than the really cheapo ones.

First problem was it came on every time the wind blew - I contacted the customer services and apparently the PIR is a Motion Sensor, so will detect bushes blowing in the wind, despite the other 4 sensor lights on the house not having the same problem. They asked me to send a video of it coming on(!) I pointed out it was therefore misdescribed as a PIR detector only detects moving heat, but whilst they are mulling that over, it has failed completely so I need a new one.

Any good brands out there?

[csearle]

This may be unhelpful, in which case I apologise in advance. If you haven't already chosen the replacement light then there are some modern ones that still provide access to the switched-live that activates the light. I recently installed some of these for example.

Chris

Hi Chris,

are these any good? I was going to ask on here for a good brand of security flood light, having purchased https://www.wickes.co.uk/Luceco-EFLD20B ... /p/205574# last year. I thought being metal bodied it might be slightly better than the really cheapo ones.

First problem was it came on every time the wind blew - I contacted the customer services and apparently the PIR is a Motion Sensor, so will detect bushes blowing in the wind, despite the other 4 sensor lights on the house not having the same problem. They asked me to send a video of it coming on(!) I pointed out it was therefore misdescribed as a PIR detector only detects moving heat, but whilst they are mulling that over, it has failed completely so I need a new one.

Any good brands out there?

Hi Paul,

Well this particular client is now on the one I linked to. It is the fifth brand we've tried since last summer! He has about 25 PIR floods dotted about his two sites, but not all of the same wattage. The jury is still out on this one. There are a couple of the smaller wattage ones that are still working but the 10-20W ones we've used seem very unreliable. It is never the plastic body that fails with time but rather the LED light and sometimes the sensor. The CCD lens eventually goes, but that is usually at least a decade away. So although a diecast body seems good to me the real test is the MTBF of the actual light source.


I would think it much more likely that customer services got it wrong about the bushes. In my experience most of these things use a charge coupled device and a lens (looking a bit like an insect's eye) to modulate the infra-red as the warm-bodied detectee crosses the field. More recently microwave sensor lights have become available that might I suppose pick up the motion of bushes but I've never experimented with that. The microwave sensor lights I've seen have all been domed ceiling/wall lights.

Chris

[MyNameIsUrl]

This thing can switch a 0.5A load when a 0.2A current is detected. So if the current of the sensed light is 200mA or more and the light to be switched draws less than 500mA then you could use it. (It would have to be mounted inside an enclosure though to be safe.

Chris

Thanks Chris, that's - in principle - exactly the function I'm looking for, but unfortunately my new light is 14W (ie about 60mA) so that won't be enough to trigger it. Googling 'Current Sensing Switch, Normally Open' returns devices which don't seem to offer the switch part of my requirement but seem more designed for instrumentation.

RC kindly provided the link: https://shop.pimoroni.com/products/curr ... ing-sensor but I don't have the background to understand what this provides - it apparently senses 0 - 5A but I'm not clear how it would switch my secondary light on.

[csearle]

RC kindly provided the link: https://shop.pimoroni.com/products/curr ... ing-sensor but I don't have the background to understand what this provides - it apparently senses 0 - 5A but I'm not clear how it would switch my secondary light on.

You would need to build some electronics (or program a chip) to detect a trigger voltage at its output and switch on a relay (or equivalent). You would also need a tiny power supply of some sort. C.

[9873210]

Well this particular client is now on the one I linked to. It is the fifth brand we've tried since last summer! He has about 25 PIR floods dotted about his two sites, but not all of the same wattage. The jury is still out on this one. There are a couple of the smaller wattage ones that are still working but the 10-20W ones we've used seem very unreliable. It is never the plastic body that fails with time but rather the LED light and sometimes the sensor. The CCD lens eventually goes, but that is usually at least a decade away. So although a diecast body seems good to me the real test is the MTBF of the actual light source.

It is ineffective to set specs for the part that doesn't break (the case) as an indirect way to upgrade the part that does break (the electronics). It may be counterproductive.

Metal is not always expensive; plastic is not always cheap. Both metal and plastics cover a huge range of materials with different costs and properties. The non-recuring engineering costs for the better types of plastic are quite high, which means they tend to be used for high volume production by manufacturers with good design and quality control. Low volume, fly-by-night knockoffs are more likely to use metal.

You might want to check the mounting. Things to look for are waterproofing (drip loops, seals), proper airflow for the heat sink, and excess vibration (very wimpy mount or bolted to motor housing). Possibly hire a different electrician (from a different firm who went to a different school) for installation. There could also be problems with the mains power, are the customers using large relay-switched motors?

[jfgw]

Even if you have bought the new light and lost the receipt, I suspect that your easiest and cheapest option is to purchase a different light such as the one linked to by csearle. Alternatively, if you can find some four-core flex that fits and have a soldering iron, you could probably adapt the one you have. It should be obvious where to connect the switched line as it will come from the sensor.


Julian F. G. W.

[9873210]

Elternatively, if you can find some four-core flex that fits and have a soldering iron, you could probably adapt the one you have. It should be obvious where to connect the switched line as it will come from the sensor.

In an integrated unit the switch could be designed for the actual load. You'd want to check carefully before doubling the load. If it's designed for an external (or secondary) load it should be documented somewhere in the data sheet.