The other day we had a power outage and apparently surge that was enough to blow out the PSU on my computer. A day or two later I've noticed the ceiling light in my office is now clicking, regularly (around once a second at an estimate.).

It only makes this sound when it's powered on, stops immediately on powering off, but doesn't always make it even when powered on.

I've included a video of it, and I'm wondering what is causing it, is it dangerous and am I likely to be able to replace the broken part or will I have to replace the entire lamp?

The clicking starts around 10 seconds in, stops momentarily and starts again:


static photo

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    I'm guessing that unit isn't meant to be repaired, and there's no way we could know what might happen next. – Daniel Griscom Sep 16 '19 at 19:11
  • I count 5 clicks - is that the sound you're talking about? – JPhi1618 Sep 16 '19 at 19:36
  • yes, except it'll sometimes go for a lot longer. – djsmiley2kStaysInside Sep 16 '19 at 20:44
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    I realize you did not post the video to show us the fine print on the sticker, but I am intrigued by it. Not many lights have 11 DIP switches. It appears to be a motion sensor. The clicks would be the sensor detecting motion and throwing the relay which switches on power. I can't quite read the legend that tells me what those DIP switch positions mean, but it appears they have the motion sensor functionality turned off. That is perhaps why this feature is news to you? – Harper - Reinstate Monica Sep 16 '19 at 20:46
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    I actually paused the video to read that label and was going to make a suggestion like Harper that the power surge could have damaged the electronics to make one of those "features" malfunction. So +1 for that suggestion and trying the switches. – JPhi1618 Sep 17 '19 at 14:00

I think it's the motion sensor, which this light is equipped with.

The motion sensor is probably not bespoke for this light, and is a commodity module. The module supplier doesn't know if it will be controlling 0.05 amps or 5, so it uses a nice burly mechanical relay that is probably overkill for this light. That's what you are hearing.

I also suspect the motion sensor may be designed for low voltage, which makes current proportionately larger (quite much larger for 12V). Current decides the relay size.

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    Amusingly changing the timer has made it turn on and off faster, that it now sounds like a machine gun ;D – djsmiley2kStaysInside Sep 17 '19 at 19:29

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