Why Does My Security Light Come On?

[Captain Spod]

There's an IR security light above the back door (the type that drives the neighbours up the wall). It comes one when someone leaves or approaches the back door but also at seemingly random times during windy weather - like this week. Never when it's still, only really blowy. Why is this?
Thanks in advance.

CS

[Tuvok]

Something is triggering it - perhaps something that has blown across the path of the sensor.

[murraymints]

Presumably it's a motion detector....must be picking up bits flying around in the wind !

[tonyav]

Are there any trees or bushes blowing about close to it ?, CS.

[The Builder]

Plants waving in the wind I guess, Captain.
You could try introducing a mask into the sensor to restrict or narrow its field of detection.
Or reduce its sensitivity.

[TWR]

Wind

[chrissa1]

Cats, dogs.

[Captain Spod]

Thanks for all these but, well, no! IR works on detecting heat, not movement and there are never any dogs or cats; birds don't visit at night. Wind isn't hot. Unlikely to be bats, any other suggestions?

[TWR]

Captain, the sensor on ours does the same " Frequent when windy.

[Peter Pedant]

.

because..... there is someone there.....

[jomifl]

If bushes are masking a background of a different temperature, a path or a wall for example then when they move and expose the background the light will come on.

[BRIGHT SPARK]

Is the boiler flue anywhere near?

[beso]

Pockets of relatively warmer air moving by in the turbulence of a breeze can set the sensor off. The heat can be picked up from anything warmer than the air.