4-digit LED clock

Discussion in 'The Projects Forum' started by cmsch180, Jun 26, 2008.

  1. cmsch180

    Thread Starter Member

    Jun 26, 2008
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    hello all, I'm new to this site, i was wondering if any of you guys could help me out with something, i have a 4" 4 digit 7 segment LED display that i would like to make into a clock, but im confused as to the wiring of the display it only has 17 pins on the connector:confused:, any help or ideas would be appreciated. thanks
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Do you have a part number for the LED display?

    You will probably find that your display was designed for multiplexing; there are 7 leads used for segments a, b, c, d, e, f, and g, and another one or two used for the colon. You probably have an AM/PM indicator on there as well, maybe even an "alarm on" indicator.

    The other leads are either common cathodes or common anodes for each of the number displays.
     
  3. cmsch180

    Thread Starter Member

    Jun 26, 2008
    12
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    unfortunately no there are no part numbers on it, and the way you described it, it would have to have 31 pins instead of 17, and it does have the AM/PM, and "alarm on" indicators.
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,645
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    Hello,

    If the display has only 17 pins, it will be multiplexed.
    To built a clock with it you have to know how it should be connected.
    It is also importend to know if it is common cathode or common anode.

    Greetings,
    Bertus
     
  5. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    It shouldn't be too difficult to work it out by systematically applying current to the pins.
     
  6. cmsch180

    Thread Starter Member

    Jun 26, 2008
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    ok, I'll try that and see if i can figure anything out
    and could someone give me a quick explanation of multiplexing?
     
  7. bertus

    Administrator

    Apr 5, 2008
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  8. cmsch180

    Thread Starter Member

    Jun 26, 2008
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    ok i think i understand how it works now thanks
     
  9. cmsch180

    Thread Starter Member

    Jun 26, 2008
    12
    0
    ok, i found a driver for the display(TB62709N) the clock ic (DS1307) and i have a control crystal(DS32KHZ-N) could anyone help me with a simple way to hook them all up? and if i need any other parts...:confused:

    Data sheet for display driver will be an attachment

    here is the data sheet for the clock ic
    http://datasheets.maxim-ic.com/en/ds/DS1307.pdf
     
    Last edited: Jun 28, 2008
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