Pir external security lights

[paul243]

I need to fit several security lights at the rear of the house, preferably with built in sensors.
There are several small trees/bushes within 20-30 feet and a large magnolia approx 20 feet high.
Can any one please advise which type of light to fit which will not be triggered by the trees moving but will detect intruders?
Are all PIRS the same?
Thanks

 

[JohnW2]

There are several small trees/bushes within 20-30 feet and a large magnolia approx 20 feet high.
Can any one please advise which type of light to fit which will not be triggered by the trees moving but will detect intruders?

If my experience is anything to go by, I fear that you are probably asking for the impossible!

Kind Regards, John

 

[RF Lighting]

Get decent separate pirs with sensitivity adjustment, and make sure they’re aimed where you want to detect, and if necessary, masked where you don’t.

 

[JohnW2]

Get decent separate pirs with sensitivity adjustment, and make sure they’re aimed where you want to detect, and if necessary, masked where you don’t.

It obviously 'depends' (upon the situation, and on what one wants to achieve).

I tried the approach you suggest for my house. However, there are so many trees, hedges and shrubs around (it doesn't take much of a shrub or hedge if the wind is strong) that by the time I had positioned, adjusted and masked the sensors enough to avoid most nuisance activation, I was left with any number of approach routes that an intruder could take being essentially 'unprotected'. Even ones I pointed only at 'the house' got activated by wind-related movement of 'er indoors' hanging baskets

Eventually I had to resort to a much more sophisticated 'intelligent' system which required multiple PIRs to be activated in certain orders and within certain time windows in order for the system to conclude that it had probably detected an intruder (or large animal ).

Kind Regards, John

 

[oldbutnotdead]

I've got 2 of Screwfix own brand LED floods, one with integral PIR & one with separate PIR (The integral PIR failed but the lamp still worked....).
Well worth getting separate PIR, gives you loads more options on lamp focus.
As for sensitivity, these things are excellent. They don't trigger when the nearby plum tree is thrashing in the wind but fox or cat strolls past and ping, lights on.
To be honest, false triggers aren't really a big deal now cos the power consumption is so low. Make sure you mask them or point them so they're not blaring into your windows or your neighbours windows and off you go

 

[JohnW2]

...As for sensitivity, these things are excellent. They don't trigger when the nearby plum tree is thrashing in the wind ....

You're lucky! However, it does depend upon many factors, like weather and time of day....

One has to remember that (unlike a doppler radar detector) PIRs do not detect movement, per se, but, rather, they detect movement of temperature changes across its matrix of detectors.

In the early evening, the leaves and branches of your plumb tree are likely to be at a similar temperature to the surrounding air and 'background' - so, no matter how much it trashes around, a PIR will 'see nothing'. However, particularly if the day was warm and the skies clear, in the middle of the night the air temperature is probably appreciably lower than the temp of the tree, so any movement of the tree will be detected as movement of 'warmer spots' across the cooler 'background'.

My immediate neighbour may well not even be aware of this but, although her PIR lights don't seem to often trigger because of wind in the evenings, they trigger very frequently in the middle of the night if it is windy.

Kind Regards, John

 

[sparkymarka]

Gjd lighting system ... not cheap but been around since the 80s