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Controllable Dimmer??? — Parallax Forums

Controllable Dimmer???

lboucherlboucher Posts: 139
edited 2008-12-31 00:08 in General Discussion
Hi All

So i am thinking about controlling my christmas lights next year, and i have a question.
I want to do it with a cheap Triac and optoisolator. I know i can dim the circuit using a POT, like in the attached diagram. How do i get controll over this from a microcontroller?
Does anyone know a good part number?

THanks
640 x 480 - 2K

Comments

  • SRLMSRLM Posts: 5,045
    edited 2008-12-30 20:41
    There are digital pots available that you can control with a microcontroller.
  • LeonLeon Posts: 7,620
    edited 2008-12-30 21:37
    What sort of lamps are they? PWM might be the best way, if you are using an MCU.

    Leon

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  • kwinnkwinn Posts: 8,697
    edited 2008-12-31 00:08
    If you have a fast enough micro you could detect the zero crossing of the AC line and send a delayed pulse out on a pin to trigger the triac. Delaying the pulse from 0 to 8.3 ms would vary the brightness from 100% to 0%.
    You need to be very careful to isolate the AC voltage from the micro.
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