View Full Version : Nightlights
04-19-2012, 03:47 AM
I was plugging in some nightlights in my home which sense the ambient light cast upon them to either turn on or remain unlit. When I went to the garage and plugged one in, I considered (and eventually did) plugging in a second one adjacent to the first one to have double the lumens in the dark (They both worked, but...). That's when it hit me (like a lightbulb), how many of these nightlights can someone install side-by-side in total darkness until their lumens eventually cancels out their intended purpose? Or if ONE very powerful one would cancel itself out? Where's the, "Event Horizon?" Please help. Thanks.
04-19-2012, 03:53 AM
Anyone else immediately think of the Weeping Angels?
Won't the answer to the question depend on the sensitivity of the particular brand of nightlight? Would the answer be when output is equal or greater than that?
04-19-2012, 03:58 AM
Sure, but at what point? Sensitivity should be irrelavent, seeing that enough of them would eventually reach, "That point."
04-19-2012, 04:27 AM
Maybe I don't understand the question.
If the threshold of the photoelectric receiver is sensitive enough to turn on/off the nightlight at 2 lumens (or whatever the proper term is), then when you have enough nightlights to equal that, you're at "that point" and the world will implode. (No, just kidding. Just your garage will.)
What's the difference between adding nightlights and bringing in more and more tiny flashlights or slowly turning up a dimmer switch?
04-19-2012, 08:58 AM
It depends on the physical properties of the nightlight.
As a thought experiment consider dismantling the night and arranging its parts so that the light sensor is directly in front of the light producer (bulb/LED/whatever).
With that arrangement the nightlight might* oscillate constantly turning itself on/off at a speed determined by the latency of it's components going from "off" to "bright enough to trigger the off function". I say might because if the light threshold for the off state is above the lumens produced by a single nightlight then it would still operate just like you would expect it to.
So the answer in this case would be "ONE".
If you arrange a group of nightlights in such a way as to trigger all or some of them to shut off then you would get anywhere from a few of them oscillating on/off to the entire set oscillating on/off. The physical arrangement of the lights and the component latencies would determine what happens.
04-19-2012, 09:07 AM
If you arrange a group of nightlights in such a way as to trigger all or some of them to shut off then you would get anywhere from a few of them oscillating on/off to the entire set oscillating on/off. The physical arrangement of the lights and the component latencies would determine what happens.Sounds like fun! Can someone post a video?
04-19-2012, 09:19 AM
i had a nightlight event.
a bathroom electrical receptacle that was just below the toilet paper dispenser. i put in a photosensored LED nightlight that was bright enough for room navigation.
if the toilet paper hung down in front of the nightlight (not me [behind and short to enable one hand snap] it was the spouse [front/back, long/short, no rhyme or reason]) then when the light triggered on it would reflect into the photosensor and shut off. it would then cycle on and off until the paper was rolled up, out of in front of the light.
if the ambient light level was low enough the paper might even filter enough light and start it triggering.
04-19-2012, 09:28 AM
Distance will matter, so you might get an exciting, erratic pattern of lights turning off and on as light-killing levels of light ebb and flow through the room. At least if the on/off latency is sufficiently slow.
04-19-2012, 01:49 PM
You will notice many photocell-controlled lights flashing at sunrise/sunset. The ambient light becomes just dark enough to trigger the light, and it turns on, which brightens the ambient enough to turn itself off. Rinse, lather, repeat - until it gets dark enough.
04-19-2012, 08:42 PM
I've had photo-sensor nightlights flicker, when they get to "that point"
it's actually just a little dimmer than normal, with a fast visible flicker.
04-19-2012, 10:19 PM
consider dismantling the night
This minor typo is oddly poetic.
04-21-2012, 10:45 PM
vBulletin® v3.7.3, Copyright ©2000-2013, Jelsoft Enterprises Ltd.