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Circuit request - digital led clock (studio timepiece)

Discussion in 'Electronic Design' started by [email protected], Apr 10, 2013.

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  1. Guest

    Hi ALL,

    I have no design knowledge but a little understanding and the ability to put a circuit together. My soldering etc. is reasonable.

    I really really really would like to put together a digital led clock with:

    Analog style round face with digital led time readout in the middle
    ie ... 22:10

    12 static hour leds around the face

    60 sequenced leds for seconds led t 12 always on.
    - sequence progresses 1 led, 2 leds .... 58 leds, 59 leds ..
    - remaining 59 leds clear at 60 seconds
    - sequence starts again at 1 second pas 12 postion

    The 60 leds obviously need to tie in to the led digital time so taht the minute changes as the 60 leds reset to (59 off) and begen again.

    I'll obviously need a way of setting the time too I guess. ALso Battery operation would be preferable if possible but DC in might be okay. Both may be better - I don't know, I guess it depends on the power requirements of the circuit.

    There is an android app that emulates this exact behaviour ....

    Google play app:

    I'd be really grateful for any help at all. I may be willing to PAY a little for more comprehensive instructions. (Paypal only)

    Thank you for your time.
  2. mike

    mike Guest

    Ask yourself what you're gonna use it for.
    Then do the math and calculate how accurate the timebase has to be.
    If you don't want to be resetting it all the time, you need
    a very accurate timebase. There's a whole bunch of seconds in a year.

    I'm not saying it can't be done, because it's done all the time.
    But you don't start with a random crystal plugged into a random
    oscillator and expect it to be stable over temperature.
    And if you expect to tune it, what equipment will be required for that
    level of accuracy? Pay attention to that up front.

    You have two problems.
    1)an analog problem generating a reference timebase.
    2)a digital problem that counts the clocks and lights the leds.
    Don't ignore the first till the end. I'd start with the timebase.

    There's a cognitive discontinuity in your requirements. The 12 static
    hour leds beg the question, "what's the minute?" They don't add to
    the time readout, but do add some confusion.
    Of course, that's just my's your project.

    One thing to consider is why you're doing this at all.
    if your objective is to learn a skill that can be used for other projects,
    I'd bite the bullet and use a microcontroller. Once you get past
    the initial setup of the programming environment, slow stuff like
    this is trivial to do in software. And when you change your mind,
    and you will, software is much easier to change. Even if you're
    gonna build dedicated hardware, having a simulation on the screen
    of your PC is a good way to get the bugs out without having to
    rewire a bunch of hardware.

    I've taken it a step further. Almost everything I do is in software
    on an old Palm3c PDA. Full graphic display and touch input.
    and the whole thing can be had for less than a buck at a recycling center
    or garage sale or...
  3. hamilton

    hamilton Guest
  4. Ecnerwal

    Ecnerwal Guest

    There is an android app that emulates this exact behaviour .... If you simply want something that looks like this, your cheapest
    solution in both time and money will be to buy an old android phone (I
    dropped a whopping $38 on one recently) and run the app. If you want it
    big, find a Google TV, which is about the largest screen android device
    out there, or use a phone/tablet with an HDMI out to another large
    screen. With WiFi available, you don't need to activate/connect the
    phone to the phone network to load the app, and you can still get the
    time (and use it to call 911 if needed, since that's available even on a
    "disconnected" cell phone.)
  5. Guest

    Thanks for all the comments. I checke dthe price of android tabs and you know what - you are right. It hardly seems worth building when tabs are so cheap.

    Thanks again.
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