PIR security lights too sensitive

Most PIR security lights don't have a sensitivity control, just light level and on time settings. Small birds flying across the beam, insects on the lens or foxes running in and out of the garden will activate them, so this could be what you're seeing. The only reasonable advice I can give, is for you to change the fitting for a more expensive one that contains something called double knock circuitry. This controls the light by only allowing two detections within a set time period on the sensor before the light is switched on.

You could try masking the top part of the sensor lens with a piece of insulating tape. Just a thin strip across the top of the lens. This reduces the range of the sensor slightly without closing it down completely to any intrusions.

First, put a bit of foil over the sensor. Does it still go on and off? If so, then it's faulty.

Do you own a camcorder? If so, pointing it at the lighted area to see if anything is triggering it may work. Any gas flues nearby?

In message , JM writes

if all obvious avenues that are being suggested fail then consider local radio transmitters, taxis CB police etc. A lot of the cheaper PIR's are RF (radio frequency) sensitive and can be triggered by quite low amounts of power. There is no easy cure for this unfortunately except maybe buying a better quality one with adequate filtering. Hopefully it will be something like a cat or central heating flue that is your problem.

Heat wafting from under the bonnet of my parked car seems to do it as well.

Just apply some black pvc tape to mask-off parts of the sensor - they can have a wide angle of detection and you may need to experiment a bit.

Dave

Depending on the tape, black insulation tape can be pretty transparent in the thermal IR - you may be better off using it to stick down aluminium foil.

Chris

Insulating tape should be OK though, as it's only to try to reduce the sensitivity of, or deflect it slightly off, the IR detector.

Thanks to everyone for their suggestions - sorry I didn't reply sooner.

Looks like the insulation tape (possibly with foil) solution is the best choice to start with - I'll give it a go.

John.