photo sensor

Thread Starter

k7elp60

Joined Nov 4, 2008
562
I'm working on a project to turn some night lights on when it gets near dark outside. The electronics to turn on and time the lights is not a problem. I am having trouble finding a photo sensor that is weather proof that I can mount on a weather proof box. Since the the lights are 12V the voltage is 12VDC. I am looking for either a photo cell or a sensor that is has some form of weather proof encloser.
Ned​
 

Austin Clark

Joined Dec 28, 2011
412
I'm working on a project to turn some night lights on when it gets near dark outside. The electronics to turn on and time the lights is not a problem. I am having trouble finding a photo sensor that is weather proof that I can mount on a weather proof box. Since the the lights are 12V the voltage is 12VDC. I am looking for either a photo cell or a sensor that is has some form of weather proof encloser.
Ned​
I'd recommend just using a transparent box. Mount your electronics, seal, and go.
 

wayneh

Joined Sep 9, 2010
17,496
The big box hardware stores have such things for controlling decorative, security, or holiday lights. Usually near the motion detector lights.
 

Thread Starter

k7elp60

Joined Nov 4, 2008
562
The big box hardware stores have such things for controlling decorative, security, or holiday lights. Usually near the motion detector lights.
I have seen them in the big box hardware stores, but was under the impression they are set up for line voltage. I do some more checking, thanks for the info.
Ned
 

wayneh

Joined Sep 9, 2010
17,496
Ah, well that's true. I'm not sure if/how you could adapt something to your needs. Just try Googling "12V photocell switch". Lots of stuff.
 

tubeguy

Joined Nov 3, 2012
1,157
You could get a photocell from one of those small night lights. (I just noticed one I have in my bathroom).
I found some specs on a typical cell - 200k ohms dark to 10K ohms light, 1ma current.
Could use a comparator -> transistor -> relay to run the lights.
 

Thread Starter

k7elp60

Joined Nov 4, 2008
562
You could get a photocell from one of those small night lights. (I just noticed one I have in my bathroom).
I found some specs on a typical cell - 200k ohms dark to 10K ohms light, 1ma current.
Could use a comparator -> transistor -> relay to run the lights.
So far that is the plan. The sensor was the part I was looking far. I may use a power mosfet instead of a relay to turn on the lights however.
 

wayneh

Joined Sep 9, 2010
17,496
I'd use the MOSFET, too.

Many of those cheap solar landscape lights have a CdS cell built into them. Since you can get the lights almost free this time of year, and they include a battery, this is probably your cheapest local option to get a sensor. If you don't mind tearing one apart.
 
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