LED configuration, how to set up?

Discussion in 'The Projects Forum' started by BobJoe, Oct 10, 2006.

  1. BobJoe

    Thread Starter Member

    Oct 7, 2006
    16
    0
    Hey:
    I plan on building a set up that has 15 or so LEDs and having them come on by incriments of a little less than .1 volt. I don't think it would be hard to build with those little ideas but heres the kicker, I only want one LED on at a time, maybe have on slowly fad in as the other fads out. Not to sure how one would go about that. It's for my car doing a reading from my O2 sensor, and I was thinking about lining up the lights red then green then blue, having 5 of each. is this possible? If so, how?
    Thanx:
    BobJoe
     
  2. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    An op amp driving 2 x cascaded LM3914's in "DOT" mode should do the trick.
     
  3. BobJoe

    Thread Starter Member

    Oct 7, 2006
    16
    0
    Hey,
    I love greek! Lol. I'll look those up later.
    thanx
    BobJoe
     
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Would something like this work to accomplish the fade-in and fade-out?
     
  5. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    Hi,

    I doubt it, LED's are current driven devices, so you'd only get a minor fade effect (and then there's the chance of it all going down in oscillations).
    But IIRC, the LM3914 allready has the effect of gradually changing.
     
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