Need help with a photocell.

Discussion in 'The Projects Forum' started by Mikiver, Nov 28, 2010.

  1. retched

    AAC Fanatic!

    Dec 5, 2009
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    debe, is that the stock LED?
     
  2. debe

    Senior Member

    Sep 21, 2010
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    Yes it was the single led that was in the solar light & it also only had a single AA nicad in it.
     
  3. retched

    AAC Fanatic!

    Dec 5, 2009
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    You got your moneys worth out of that little lamp!

    How often must you change the battery?
     
  4. debe

    Senior Member

    Sep 21, 2010
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    Still has orig battery in it. Just decided to try & draw the circuit in one, The solar panel in it turns the LED off during the day when its charging, obviously the transistor is boosting the 1.2V for the LED as its quite bright.
     
  5. Audioguru

    Expert

    Dec 20, 2007
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    The solar panel of a cheap solar garden light must be in direct sunlight all day long for its battery cell to light the LED dimmly for an hour at night in winter. The LED does not light following a cloudy day.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    A single, cheap LED at half it's rated current capacity will be plenty of light for this use.
    My suggestion wasn't to use the solar panel for battery charging, just the internal electronics. These will give you the CdS photocell for on/off control and as a bonus you'll get the voltage boost circuitry so that you can squeeze more out of the batteries on each charge. These parts cost <$2 and will do a much better job than something you whip up on your own at higher cost and trouble.

    Still, I think you'll only get 2-3 nights out of a full charge unless you go to a larger battery pack (maybe 4 AAs in parallel?). Using a motion detector is a better suggestion.
     
  7. debe

    Senior Member

    Sep 21, 2010
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    Hi Audioguru, I can asure you here in Austalia we have plenty of sunshine & these Leds will stay a light till morning when they switch off & the solar recharges the battery
     
  8. MikeK

    Member

    Apr 1, 2016
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    Is the DC-DC converter mentioned a Joule Thief? I don't see a coil. I would like to construct a circuit like this using a Joule Thief to use up old batteries my camera kicks out way too soon as weak. I can use the light for lots of uses, like a stink bug trap. Old batteries are usually not ni-cad, so solar charging is not necessary. I'm just wondering if a Joule Thief can come up with enough power to operate the daylight sensor circuit.
     
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