Sunrise LED fader

Discussion in 'The Projects Forum' started by w.irving, Oct 18, 2014.

  1. w.irving

    Thread Starter New Member

    Oct 18, 2014
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    0
    I'm looking for a simple circuit that would drive a large number of LEDs for a sunrise simulator. It would obviously have to be able to perform a long fade up phase, up to an hour.
    Have looked at various circuits, including Bill Marsden's excellent posts, but not managed to think of anything I could work with, fader wise. Could anyone point me in the right direction?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    You could have a look at PWM control with a counter and a DAC for the control voltage of the PWM.
    For instance a 256 step counter will raise the voltage on the DAC about every 14 seconds.

    Bertus
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Even a lowly Arduino has PWM'able pins with duty cycles ranging from 0/255 to 255/255 at a frequency of 500Hz. A 14sec delay is trivial.
    I could write the code in ~ 5min.
     
  4. w.irving

    Thread Starter New Member

    Oct 18, 2014
    2
    0
    Thanks for your replies!
    The oscillator - counter - DAC approach seems a bit too complex for me.
    Have more experience with web development than electronics, so perhaps an Arduino with a MOSFET would be the easiest solution after all? Would an Arduino mini or nano be enough? I am just looking for anything with PWM capable output right?
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
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    A nano is quick and easy. The mini would do it, but requires a bit more wiring. If you need to build ten of them, do the development on a nano and incorporate minis into the final product...
    If you need a thousand, learn how to program an ARM or PIC.
     
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