This LED sequence

Discussion in 'General Electronics Chat' started by XalaX, Jul 29, 2010.

  1. XalaX

    Thread Starter New Member

    Jul 29, 2010
    2
    0
    Hi,
    i'm a newbie of this forum. I don't understand so much about electronics but i'm good in building my own circuits from projects.

    I would like to have help in making this kind of led sequence.
    If you can post me some scheme or project or link, please.

    The circuit has to turn on and off about 20 leds in this way:

    00000000000000000000
    00000000000000000001
    00000000000000000011
    00000000000000000111
    00000000000000001111
    and so on...
    11111111111111111111
    01111111111111111111
    00111111111111111111
    and so on...
    00000000000000001111
    00000000000000000111
    00000000000000000011
    00000000000000000001

    Thank you for helping me.

    Kind regards

    PS forgive my bad english, i'm from sicily :p
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Welcome to the forums. Your English is very good.

    One of our members has been working with 555 timers and LED's for some time. You might get some tips from his article - http://forum.allaboutcircuits.com/showthread.php?t=19075

    My take on your circuit would be to use a bidirectional shift register - actually 5 of them (74LS194). You would also need additional external logic to make the last bit 0 when then maximum count of 20 was reached.

    And then maybe someone else will have a better idea.
     
  3. XalaX

    Thread Starter New Member

    Jul 29, 2010
    2
    0
    thank you!
    it's time to work for me now ;)
     
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