photo sensor

Discussion in 'The Projects Forum' started by k7elp60, Nov 16, 2012.

  1. k7elp60

    Thread Starter Senior Member

    Nov 4, 2008
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    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 ​
     
  2. Austin Clark

    Member

    Dec 28, 2011
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    I'd recommend just using a transparent box. Mount your electronics, seal, and go.
     
  3. wayneh

    Expert

    Sep 9, 2010
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    The big box hardware stores have such things for controlling decorative, security, or holiday lights. Usually near the motion detector lights.
     
  4. k7elp60

    Thread Starter Senior Member

    Nov 4, 2008
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    I hadn't thought of that. The boxes I used on a similar project were nema 4 and had a clear lid. Thanks for the idea.
    Ned
     
  5. k7elp60

    Thread Starter Senior Member

    Nov 4, 2008
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    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
     
  6. wayneh

    Expert

    Sep 9, 2010
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    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.
     
  7. tubeguy

    Well-Known Member

    Nov 3, 2012
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    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.
     
  8. k7elp60

    Thread Starter Senior Member

    Nov 4, 2008
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    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.
     
  9. wayneh

    Expert

    Sep 9, 2010
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    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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