Flip-flop controlling multiple LED's?

Discussion in 'The Projects Forum' started by microelectronix, Dec 10, 2008.

  1. microelectronix

    Thread Starter Member

    Jan 21, 2008
    20
    0
    Hello all,

    I need to control 12 LED's (they're all either on or off) using a strobed input - A pulse to turn them all on, and a pulse to turn them all off. The signal will be coming from a chip, probably a multiplexer. I was thinkin' I'd use a flip-flop to store the state, which would drive a BJT to power the LED's?

    I guess I can break it down to two things:

    1) What is an efficient method to store the state of the LED's (on/off)

    2) How can I control LED's using a logic input?

    Thanks all!
     
  2. microelectronix

    Thread Starter Member

    Jan 21, 2008
    20
    0
    Actually I read this site and answered one of my questions on my own... how to use a BJT to control the LED's.

    But I'd still like some input on how best to store the state / alter it.

    Thanks!
     
  3. bnfdvn

    Member

    Dec 8, 2008
    21
    0
    You could use a JK flip flop, tie the J and K inputs high and connect your pulse input to the clock input. Each time the clock input is pulsed, it will toggle the outputs. Will this do what you want??
     
  4. microelectronix

    Thread Starter Member

    Jan 21, 2008
    20
    0
    Yes, that sounds great actually! Thank you very much.
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Don't forget debouncing the switch, something like this.

    [​IMG]
     
  6. microelectronix

    Thread Starter Member

    Jan 21, 2008
    20
    0
    Can it be done using D-type flip flops? I have a SN74HCT74N (dual D-type flip flops) that I'd like to try it out with. I'm pretty sure I actually have many of these, which would be great as I wouldn't have to buy anything.
     
  7. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    I remember seeing something like that. Feed the inverted Q back to the D, it becomes a clocked flip flop.
     
  8. seesoe

    Active Member

    Dec 7, 2008
    99
    0
Loading...