auto night sensor light fitting

[Mikeyboy]

Bought one of these from Wilkos yesterday. Idea was, fit it in my hall light, and it will come on as it goes dark. Good for security and convenience of the first person home. I tried it out this morning, and it came on immediately, ven though its pretty bright daylight, though admittedly it is overcast, I wouldn't describe it as dark in any sense. The location is basically next to the front door, which has masses of glass in it.

Does this suggest that it is only going to turn off in reallt bright sunshine? That is my "take" on the situation. Can anyone who know, please advise? Thanks.

[Dave Plowman (News)]

They're normally adjustable. Look for a plastic recessed screw, etc. Possibly with a scale round it.

[CJK]

The last one I had the adjustment was no longer present. I did a PM on a dead Osram non adjustable one & it is quite complex involving a PIC (PIC16C505) microprocessor. Based on my observations these seem to learn the lighting pattern and adapt to it. Providing it is left permanently on, it seems to adapt to the local lighting pattern in a day or two. Just don't switch it off....

Chris K

[Jonathan Campbell]

Are you talking about a device that fits between the bulb and the socket?

If so, you may find that it does not have any adjustment --- unlike external PIR-switched lights.

In the case of the one I have (turns on when 'dark' and a sound is made), it is in the hall about one metre from a door with a lot of glass and facing south. In winter 'it thinks' it is dark for most of the day

-- at times when you would never think of switching on a light.

There will be a light sensor somewhere; it may be possible to arrange that it faces the door.

Best regards,

Jon C.

[Harry Bloomfield]

Mikeyboy wrote on 15/02/2009 :

To allow test and setting up during daylight, they often supply the units with a black sticky label or similar over the light sensor. Once tested and working you are supposed to remove this - Have you checked for this?

[John]

switch off.

[Harry Bloomfield]

John has brought this to us :

Not quite - the sensor can be and is ignored when the light has been turned on to prevent them cycling, besides which there a tremendous difference between the levels of daylight and that provided by a lamp.

[Mikeyboy]

So is the consensus that I should leave it on all day and allow the sensor to get used to the differences in natural light? or what? I am a little confused. Thanks for the help, by the way.

[John]

away from the sensor.

If the sensor can ignore its own light then how can it detect the daylight of the morning - I guess it would only be a simple photo cell.

[Harry Bloomfield]

John laid this down on his screen :

I don't quite follow your question...

It is simple electronic logic, as in - If light has been turned on, then ignore input from p/cell until light times out and goes off. If light is out then enable p/cell.

[CJK]

it was first plugged in it did not work but after a few days it settled down & coped with varying day lengths. When it finally gave up I investigated & the logic was based on a microcontroller with embedded non volatile memory. My guess was that it was learning the varying light levels & setting the switch point accordingly. The replacement (different mfr) is doing the same.

This may be the norm for those without adjustment. Worth a try just leaving it for a few days and see if it sorts itself out if there is no adjustment.

Chris K

[John]

[Martin Pentreath]

I've got three dusk-to-dawn lights at various places outside our house. The two which are built into lamps are pretty rubbish in my view. They turn the light on far too early and off far too late. I'm talking here about sensors located outside in broad daylight, in one case pointing upwards towards the southern sky. They only have 7 watt bulbs in them, so lecky consumption is not a big deal, but the whole point of the things was to increase security, and outside lights switched on in daylight says "empty house" to me. The last time I fitted an outside light I bought one with no sensor and bought a fairly sophisticated, fully-adjustable sensor unit separately. That one works fine.

To sum up: (1) built-in light sensors are rubbish, (2) if you put them indoors they'll probably be on for 23 hours a day, (3) buy a decent one separately, and (4) why can light manufacturers make sensors which come on at a sensible time?

Cheers!

Martin

[The Medway Handyman]

Agreed. I can't get my head around this at all.

I have a dawn/dusk light outside the front door. Outside the attached garage I have a 500w security light activated by a switch. When I turn this on the dawn/dusk goes out, when I turn it off the D/D comes back on.

So how come the D/D doesn't react to its own light & turn off?