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Turning a light on and off with momentary switch

Discussion in 'Electronic Basics' started by Chris W, Feb 16, 2005.

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  1. First question: can I use more than one stage of the LED sequencer to
    prolong the duration of an LED being on? For example, if I want the first
    LED to stay on twice as long as the 2nd and 3rd LEDs, is it sufficient to
    connect the first two outputs to the first LED, and then only one output to
    each of the other two? In other words, is it a problem to connect two
    outputs together without using diodes?

    Second question: I have decided to use the approach you recommended (using
    the 4017 with transistors to boost the outputs, as depicted in the link
    above). In order to drive the process, I would like to use a combination of
    the simple toggle provided here:
    and the 555 for automatic operation. In other words, I would like to be
    able to switch back and forth between using a momentary switch to control
    the LEDs and using the 555 to automatically cycle through them.
    Could someone please explain the circuit design necessary for switching
    back and forth between the two?

    Third question: Alternatively, since the 555 can be used as a debouncer by
    itself, is it possible to configure the circuit so the 555 could actually be
    used both as a debouncer for manual operation and as a timer (which would
    obviate the need for the simple toggle above)?

    Fourth question (I think I've well exceeded my quota here): is there any
    good freeware or open source software for designing circuits and printing
    out those designs?

    Thanks a bunch,
  2. Guest

    Yes, it is a problem, you need diodes. See my traffic light
    circuit for an example:

  3. Perfect - thank you. Also, that seems like an elegant/parsimonious circuit

    Incidentally, what software do you use for rendering your circuits designs
    as they appear on the links you have provided?

    Thanks again,
  4. Guest

    Incidentally, what software do you use for rendering your
    The software is an old DOS program called "Colorix VGA Paint" 1989.

    It's similar to Windows "Paint" with more features.
    It's easy to copy and paste, and move things around.
    Windows "Paint" can do the same thing, but has limited
    editing features.

  5. Impressive. Because of the high quality, I didn't realize that you drew
    them manually. I thought they were created by an electronics CAD program.

    Does Colorix VGA Paint run in a DOS window on a pentium class machine?

  6. Guest

    Does Colorix VGA Paint run in a DOS window on
    Yes, it runs in a DOS window on Win 95,98,2000 and
    Xp. But I forgot to mention the Colorix program produces .GIF files
    directly while Windows Paint only produces .BMP files which need
    conversion. There are utilities to convert formats, but it's nice to
    get the finished drawing in the right format without conversion

    The first few drawings took some time, but as the library grew, I can
    usually find a drawing close to what I need, start with that, and just
    move things around to create a new drawing.

  7. FYI, Paint under XP can save files as GIF, TIFF, JPG, and PNG, as well
    as various levels of bitmap. You need to change the popup menu on the
    saveas dialog to indicate the proper format.

    Robert Monsen

    "Your Highness, I have no need of this hypothesis."
    - Pierre Laplace (1749-1827), to Napoleon,
    on why his works on celestial mechanics make no mention of God.
  8. It works the same for ME as well.
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