Sensor Placement

[sparkypenguin]

Hi all,

I am currently self building a 2 storey house and I have some Robus R180 sensors IP44 to fit that will activate 50W LED security lights via a relay system which has been discussed in another thread.
I am first fixing my house and my questions for this thread are all about the location of the sensors and hence the cabling for the sensors.

The maximum recommended height is 2.5m and my eaves height is approx. 5m and as I have no electric at the moment it is going to be difficult to test how well they work at any height so any thoughts welcome on this 2.5m v 5m placement.

Another option is to mount under the external window sills of my first floor windows, this will be approx. the correct height and will probably look ok, however are there any draw backs to this?
My first though would be rain run off but surely this would happen if they were at any unsheltered height?

Also down the sides of the house are paths of approx. 1.5m wide so I am thinking of mounting the sensor at the eaves height of 5m and pointing them directly down. My thought process is that the senor does not know it is pointing down so anybody walking along these corridors will be well within it's 12m range and as they will be walking across the sensors view it should readily pick them up.

Any thoughts would be appreciated.
Thanks Mark.

 

[oldbutnotdead]

Under the sills should be fine. Main problem with mounting the things higher is you lose your effective range- if you are only interested in a path beside the house wall then not really an issue. Sub problem is detecting thermal activity from your neighbours' garden...

 

[Taylortwocities]

Gotchas are things like neighbour’s extractor fan outlet/ boiler flues and the sensor getting confused by other lights (yours or someone else’s)

 

[ericmark]

I have used all sorts of sensors, photoelectric beams can use sender/receiver or reflectors, and the distance can vary a lot, using passive inferred will only would with something emitting heat, but you can also get movement sensors that send out a beam and look for the dopier effect on the frequency when some thing moves.

I know with passive inferred reverse up drive no lights, need to drive in with car radiator facing the detector. I would guess these will have a problem with electric cars?

In theory passive inferred should not be affected with wind blowing trees but I know they do, even seen the with on when a radio is used. I would walk the dog and have a chat on the local repeater and see all these security lights switch on every time I pressed the PPT.

Central heating boilers and other lights can also cause problems, next door had a security light, and I had a simple light activated one well before they fitted on, and it would keep people awake with their large illegal 300 watt lamp, flashing on/off all night, as their light switched off, my light would switch on, which would cause theirs to switch on and mine would switch off, and the timer on theirs would hold it on for 5 minutes, then whole sequence would start again.

I fitted a small bulb, seem to remember 6 watt CFL, and disconnected the photo cell. And would only switch it on when we went out so we could see our way back. Today with LED to see to walk around a house likely does not even need 6 watt with LED, and outside lights were for me and my family, could not care less if an intruder walks into something, well serves him right, which should I make it easy for an intruder?

May be the law has changed, but when I went to college it was permitted to watch an intruder walk into danger, but you could not set a trap, so if he falls into a vehicle inspection pit it is the intruders fault, but your not allowed to dig a pit, seems glass on walls if visible is OK it is a deterrent, if not a trap so would need lights on the wall with glass so visible, but can't see it being much of a deterrent, the same with any security lamp which is often triggered by cats, one just ignores them when switching on so often, however would like to watch badgers or a fox around the house.

Real security lights are outside our visible spectrum, the allow camera to watch, but don't assist the intruder. One can follow the progress of the hedge hog all around the house. But wild life means for me passive inferred is a non starter, the bats which roust next door set them off. So I use smart switches which combines time and use of phone to switch them on. Except for the one for milkman which has the sensor low down and is solar powered.

 

[sparkypenguin]

Under the sills should be fine. Main problem with mounting the things higher is you lose your effective range- if you are only interested in a path beside the house wall then not really an issue. Sub problem is detecting thermal activity from your neighbours' garden...

Thanks for clarifying that.

Gotchas are things like neighbour’s extractor fan outlet/ boiler flues and the sensor getting confused by other lights (yours or someone else’s)

Cheers.
Will consider all of those things and anything else I can think of that may trigger them.
Is it the heat from other lights that could trigger them or the light itself?

 

[sparkypenguin]

I have used all sorts of sensors, photoelectric beams can use sender/receiver or reflectors, and the distance can vary a lot, using passive inferred will only would with something emitting heat, but you can also get movement sensors that send out a beam and look for the dopier effect on the frequency when some thing moves.

I know with passive inferred reverse up drive no lights, need to drive in with car radiator facing the detector. I would guess these will have a problem with electric cars?

In theory passive inferred should not be affected with wind blowing trees but I know they do, even seen the with on when a radio is used. I would walk the dog and have a chat on the local repeater and see all these security lights switch on every time I pressed the PPT.

Central heating boilers and other lights can also cause problems, next door had a security light, and I had a simple light activated one well before they fitted on, and it would keep people awake with their large illegal 300 watt lamp, flashing on/off all night, as their light switched off, my light would switch on, which would cause theirs to switch on and mine would switch off, and the timer on theirs would hold it on for 5 minutes, then whole sequence would start again.

I fitted a small bulb, seem to remember 6 watt CFL, and disconnected the photo cell. And would only switch it on when we went out so we could see our way back. Today with LED to see to walk around a house likely does not even need 6 watt with LED, and outside lights were for me and my family, could not care less if an intruder walks into something, well serves him right, which should I make it easy for an intruder?

May be the law has changed, but when I went to college it was permitted to watch an intruder walk into danger, but you could not set a trap, so if he falls into a vehicle inspection pit it is the intruders fault, but your not allowed to dig a pit, seems glass on walls if visible is OK it is a deterrent, if not a trap so would need lights on the wall with glass so visible, but can't see it being much of a deterrent, the same with any security lamp which is often triggered by cats, one just ignores them when switching on so often, however would like to watch badgers or a fox around the house.

Real security lights are outside our visible spectrum, the allow camera to watch, but don't assist the intruder. One can follow the progress of the hedge hog all around the house. But wild life means for me passive inferred is a non starter, the bats which roust next door set them off. So I use smart switches which combines time and use of phone to switch them on. Except for the one for milkman which has the sensor low down and is solar powered.

Thanks for reply, some interesting points which I had not thought of and will now consider.

The story about your / your neighbours security light triggering each other sounds comical but I doubt it was at the time!
Do you think other LED lights would have the same effect as they seem to emit minimal heat?

Using the lights mainly as a deterrent and also gonna have cameras / phone app etc and going to put lots of lights and sensors so if I need to adjust, replace or even turn off 1 or 2 of the sensors will hopefully not be a major issue.

I would be quite happy to see any scumbag intruder walk directly into a pit of crocodiles but not sure I'll get planning permission

 

[Taylortwocities]

Is it the heat from other lights that could trigger them or the light itself?

It is a change in heat pattern that trigger the PIR, so a light turning on shouldn’t trigger the detector.

BUT
the PIR also have an ambient light sensor(photocell). This is used so the PIR only works at night, when it is dark. So you need to think about other light sources, such as neighbours lights, street lights, etc.

 

[ericmark]

Security is complex, loads of lights can make it worse rather than better, the old story, if there is a alarm system then likely some thing worth stealing. So the bell box on the wall is not always a good thing.

We have in general two types of thieves, the pro, he would not worry about security lights, in fact it likely helps him, and the opportunist, who does not really think about what he is doing, and the lights may him/her her off, but when they trigger is important, it needs to be before the point of no return, so likely lights on all the time work better than lights triggered.

Personally I hate the light on all the time, I have one house who's lights illuminate my bedroom, but have to admit likely a better deterrent to lights on a PIR.

 

[sparkypenguin]

The lights are just one part of my security set up which will also include video cams, and a good alarm system. Appreciate that if they want to be in then they will probably get in but no reason to make it easy!
Thanks for everyones help on this.

 

[sparkypenguin]

Hi all, I am looking for a cable to use for the motion sensors.
They need a L & N feed and a SL return and ideally I want to use black outer for cosmetic reasons.
When looking on the web I have found mixed information about whether I can use 3184Y or not.
On the CPC site it states "Generally unsuitable for outdoor use", "Generally" obviously being very ambiguous!
Then on other sites, such as electricalworld, they state "Flexible Circular Wire for Indoor & Outdoor uses up to 500V", some even state suitable for lawnmowers.
They are both black 3184Y 0.75mm 4 core and earth cables but am I missing something?
Here are the links if it helps...
https://cpc.farnell.com/pro-elec/pelb0795/cable-flexible-3184y-0-75mm-black/dp/CB22806
https://www.electricalworld.com/en/Zexum-075mm-4-Core-Black-Cable-Flexible-3184Y/m-646.aspx
The cable that will be outdoors will be under the soffit and behind the motion sensor and will likely only be approx. 50mm long.

Any thoughts would be most helpful.
Mark.

 

[sparkymarka]

Ever thought of doing it right and fitting a 4 zone gjd lighting system ?

 

[bernardgreen]

will probably get in but no reason to make it easy!

Does providing them ( burglars ) with light make it easier or harder for them to find a way to get into the house ?

 

[sparkypenguin]

Ever thought of doing it right and fitting a 4 zone gjd lighting system ?

Thanks for that idea, I was going to have 8 different zones but may reign in my idea to the 4.