Infared lights

[revengus]

Hi,
I have some infared securtiy lights (PIR) that detect motion, but gradually 2 or 3 of them have started to just stay on when I turn the switch on,
Anyone got any experiennce of this?

 

[davenn]

Hi,
I have some infared securtiy lights (PIR) that detect motion, but gradually 2 or 3 of them have started to just stay on when I turn the switch on,
Anyone got any experiennce of this?

...Initially you need to open them up and check for spiders etc etc inside the units
they drive PIR's crazy.
...check that the PIR's are clean from dust etc.
...check the operation of the PIR cct it probably have a relay output, see if you can determine if its triggering. maybe its stuck in the triggered mode either cuz its failed or it has voltage across the coil all the time determine which one of those
...determine if moisture has got into the system and corrosion is possibly shorting out the cct and causing false operation.
...check the sensitivity adj trimpot and see if it has any effect on operation

those are a few things to check

 

[revengus]

Cheers for the inof, checked it all out and no apparent shorts / burning or anything else obvious. Can't hear the relay triggering and the pots do nothing. I noticed this one does nothing at all now so I totally by-passed the PIR cct and am using it as a normal floodlight for now. I will take the other one apart later and see what that looks like.
Incidentaly, the pots are marked eg. 500K730M and 2M733K are the ohm ranges or just part numbers?

 

[davenn]

Incidentaly, the pots are marked eg. 500K730M and 2M733K are the ohm ranges or just part numbers?

I would take those to be 500K Ohms and 2 Meg Ohms respectively

not sure what the 730M and the 733K markings would be

cheers
Dave