LED Comet's tail

Discussion in 'The Projects Forum' started by theatrcymraeglampy, Sep 22, 2009.

  1. theatrcymraeglampy

    Thread Starter New Member

    Sep 22, 2009
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    Hi All,

    I need to make a circuit using either 8, 10, or 12 red LED's, that will chase around in a circle, but leaving behind them a 'Comet's tail'

    I.e. One led on full power, then one led behind it slightly less bright, and then another led behind the second on less brightness again, all chasing around in a circle.

    Like a the circle on a Sky Plus box for anybody in the UK.

    Any suggestions would be welcome aswell as any kit forms that could be adapted.
     
  2. Audioguru

    Expert

    Dec 20, 2007
    10,508
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    A chaser made with a CD4017 has only one LED lighted at a time. You could add some resistors and a capacitor to each LED so that it fades off.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    There is a recent " Knight Rider " project using this effect, but do not remember the post. As a start,assuming +9V, red LED, 4017,& RC of 1/10 sec, try C 300μF,R 300Ω. There maybe something simpler.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    Did you happen to notice the link in the post above yours? :D
     
  6. ELECTRONERD

    AAC Fanatic!

    May 26, 2009
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    A coma could be difficult to make. I would suggest using Bill's recommendation.
     
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Bill,your post was not there when I started thinking, could have saved me my febel effort had I been aware of it.
     
  8. theatrcymraeglampy

    Thread Starter New Member

    Sep 22, 2009
    7
    0
    Hi,

    Thanks to everybody for their replies so far, they’ve been really helpful.

    Apologies for posts in a few new topics in the past 48 hours, have a new project on that I need help in a few areas, but I’m really glad I found this forum!
     
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