Two 7 Segs - Zero to Fifteen - Up and Down

Discussion in 'The Projects Forum' started by Davik, Jan 26, 2009.

  1. Davik

    Thread Starter New Member

    Jan 26, 2009
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    0
    I'm working on a wireless volume control system for a band, to be used during practices. I have almost the whole project working, but one part that is still left to do needs is volume level indicator, i.e. 7 segment displays.

    Essentially I need to be able to count up and down between zero and fifteen (or 1 and 16), with the display on two 7 seg displays. There are two options for inputs to control this:-

    1. Two clocks, one for counting up and one for counting down.
    2. Four inputs in a binary sequence.

    For the binary option, the counting would be limited at either end already, so that once it gets to 0 or 15, it stops, rather than looping around. For the clock option, this would need to be worked into the circuit.

    I need to stick to 4000 series ICs and the standard components.

    Anyone got any ideas?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Use a 4029 up/down counter with some external logic to freeze the clock at the extremes.
     
  3. Davik

    Thread Starter New Member

    Jan 26, 2009
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    0
    Would you use the chip in Binary mode (which takes it up to 16, and then starts back to 0, in normal operation), or in Decade mode, and just carry out to another 4029 for the second digit.

    Also, any ideas for locking the higher numbers of using logic?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Easiest to use two 4029's in BCD mode.

    your last -
    - doesn't quite translate.
     
  5. Davik

    Thread Starter New Member

    Jan 26, 2009
    3
    0
    off*

    My bad. Cheers for the suggestions, I'll have a go.
     
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