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Need Help With 12v Darkness Detector

Discussion in 'Sensors and Actuators' started by RehanIqbal, Jul 28, 2018.

  1. RehanIqbal

    RehanIqbal

    4
    0
    Jul 28, 2018
    Hey guys,
    I have been attempting to recreate a solar light (Those little outdoor garden lights) but on a much larger scale. I have attached a photo of the diagram that I was basing this off of. I have also attempted to use an LDR, but that would force me to use a relay, which I would prefer not to use. I am primarily attempting to use the solar panel as a darkness detector so that the light strip will turn on when it turns dark.
    The Led Light Strip is 12v
    and the Battery is 9v
    The reason being is that I don't need the LED at full brightness.
    Please tell me what I should change, or if I should use a different diagram.
    Regards,
    Rehan Iqbal
    Edit:
    Current problem is that the LEDs wont turn off
     

    Attached Files:

    Last edited: Jul 28, 2018
  2. Bluejets

    Bluejets

    2,981
    578
    Oct 5, 2014
    Maybe try a diode between d1 and the solar panel....??

    Did a Google and this came up ......
     

    Attached Files:

    • Led.gif
      Led.gif
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    Last edited: Jul 28, 2018
  3. Nanren888

    Nanren888

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    7
    Nov 8, 2015
    Maybe you have done this already, but a few checks might be worthwhile.
    Some strips for 12v may not run at all on 9volts. Check.
    Depending on your battery and your LED strip, some may run a battery flat rather quickly. Worth checking.
     
  4. kellys_eye

    kellys_eye

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    1,143
    Jun 25, 2010
    What's the gain of the transistor?
     
  5. RehanIqbal

    RehanIqbal

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    0
    Jul 28, 2018
    The LED works fine on the current voltage, its just a little dimmed
     
  6. RehanIqbal

    RehanIqbal

    4
    0
    Jul 28, 2018
    I used a diode that comes in those tiny garden lights, should i go out and purchase a bigger one?
     
  7. RehanIqbal

    RehanIqbal

    4
    0
    Jul 28, 2018
    the one i was attempting to use in the failed circuit was 400
     
  8. Audioguru

    Audioguru

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    517
    Sep 24, 2016
    Like I said on the other forum, of course the LEDs will not turn off because the 2V from the solar panel is not enough to turn off the PNP transistor. The voltage from the solar panel must be about the same as the emitter of the transistor, 12V or 9V depending on the battery voltage.
     
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