slow glowing LED and flashing led timed together

Discussion in 'The Projects Forum' started by modellighting, Oct 2, 2009.

  1. modellighting

    Thread Starter New Member

    Sep 27, 2009
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    I'm working on a project and need a red led to slowly glow to full brightness and when full on I need a white LED to light and both LEDs to go out at the same time. It doesn't have to be a repeating cycle

    I've only done simple 555 and 4017 led chaser circuits so this effect is beyond me.
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Not exactly as requested , but it's a start.Adjust R5 so full red LED brightness is reached by end of 10 sec timing cycle when 1/2 sec 555 is triggered to turn on white LED. D4 adjusted to give rapid discharge of C2.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    What are you talking about?
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Acidently hit post ,I guess
     
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  5. Wendy

    Moderator

    Mar 24, 2008
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    Ah, caught you mid edit. You seen this one? It works well, but the power supply has to be 9V.

    [​IMG]

    Seems to me that you could add a white LED/resistor from pin 3 to Vcc and get the same thing.
     
  6. modellighting

    Thread Starter New Member

    Sep 27, 2009
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    Ok. thanks I'll try building those.

    I'm trying to get the effect of a star trek photon torpedo launcher from the 1st movie. red building to intensity and a white flash at fire. There is a prebuilt lighting circuit for it, but I'd rather build it myself.
     
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    To shorten C2 discharge time, use an N-ch FET with an RC delay on gate, 2/10 th sec or less depending on burst time. To change C2 charging from expotential to linear try a constant current source ,replacing R4, such as LN334 adjusted for about one mA.
     
  8. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Will try thread again
     
  9. alvinthegreat

    New Member

    Oct 23, 2009
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    may i ask a question? what is the unit of the capacitors in last circuit??? is it uF? or pF? and what type of capacitor was used? also, what diode was used?
     
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