HELP: Dimming Fluorescent Lamps with Microcontroller

Discussion in 'The Projects Forum' started by crankler, Dec 15, 2010.

  1. crankler

    Thread Starter New Member

    Dec 14, 2010
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    Anyone who knows a circuit with a microcontroller to control the light output of fluorescent lamps? I have some Mark 7 0-10V dimmable ballasts which is controllable by low voltage 0-10 volts, 0.5 mA signal.

    My plan is to have the output of microcontroller connected to some circuit which will output 0 to 10 volts. Is it possible with DAC or using some relays?

    Using adjustable voltage regulator or potentiometer, as they say is inefficient. And how about using RKM-ALC which also outputs 0-10v to control LEDs? Would that setup work?

    I'm not really good in all these stuff so can anyone please help me?! Thnx in advance...
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    There are a few ways to get an analog output from a PIC, some use several pins, others use a PWM output filtered to a level.

    What accuracy/number of steps would you want?

    If the desired result is 3 levels, then using 3 digital I/O ports in a resistor ladder to generate 3 voltages would be simplest.

    If a continual dimming from dim to bright would need a PWM solution.

    Either of these methods can then be scaled to 0-10V through a transistor.

    Do you have the datasheet for the dimming ballasts?
     
  3. crankler

    Thread Starter New Member

    Dec 14, 2010
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    Using ladder of resistors may not be applicable because the microcontroller's output is only 5 volts.

    Here are the datasheets:
     
  4. crankler

    Thread Starter New Member

    Dec 14, 2010
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    I found this patent application of invention for fluorescent dimmer. The circuit used has PWM output. My problem is I don't know the part numbers of the components.
     
  5. crankler

    Thread Starter New Member

    Dec 14, 2010
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    Fluorescent dimming lamp controller:
     
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    I can see the catalog page and the pdf for a standard ballast, but I can't open the last PDF above.

    I'm looking for the min/max input requirements of the 0-10V signal, along with any noise rejection, etc.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    For the micro..Use the 0-5V PWM.. Filter to get 0-5VDC.. Op amp to scale it to 0-10VDC. (or as close as you can get to 0)

    and yes the aquarium controllers with the 0-10V output will work just fine too.
    and there are many DMX (DJ/Stage lighting) controllers that will work too.
     
  8. crankler

    Thread Starter New Member

    Dec 14, 2010
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    Philips do not give much information about the ballast. The datasheets show limited information. and they just recommend buying compatible controls available in the market. Maybe the best thing to do is either to buy the controller or make the PWM-op-amp thing to work.
     
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