Project: Digital Clock built with 7490 Decade Counters and a Hacked Quartz Clock

Discussion in 'The Completed Projects Collection' started by BlackCow, Apr 2, 2010.

  1. BlackCow

    Thread Starter Active Member

    May 11, 2009
    65
    1
    Thanks jgessling for giving me the idea of hacking a quartz analog clock for my 1 second time base.

    Video of the clock.

    The time is kept by six 7490 decade counters. The 1 Hz clock is pulsed into a 7490 wired up as a mod 10 counter (for seconds 0-9). The output of the mod 10 counter is pulsed into a 7490 wired as a mod 6 counter (for seconds 0-5). That circuit is then duplicated for the minutes (0-59). The hours are then counted by two 7490s wired up as a mod 24 counter. (0-23).

    The tens of seconds are displayed by 3 LEDs in binary. The 7 segment displays are driven by four 4511 BCD-to-7 segment decoders. I needed thirty-three 100 Ohm resistors in total for all the displays and LEDs.

    My blog post.
     
    Last edited by a moderator: Dec 27, 2011
    WannaPlay likes this.
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    It would be preferable to move the docs to this site. We have had extensive bad experiences with the other, just pack them in a zip file, they should fit in this site.
     
  3. BlackCow

    Thread Starter Active Member

    May 11, 2009
    65
    1
    Yeah I was having trouble attaching the schematic as a pdf. Zipping it worked fine, thanks.
     
  4. m2007d

    New Member

    Apr 2, 2010
    1
    0
    really nice
     
  5. ventori

    New Member

    Jun 2, 2010
    1
    0
    thanks you
     
  6. jgessling

    Active Member

    Jul 31, 2009
    74
    14
    Very neatly done.
     
  7. Bill B

    Active Member

    Nov 29, 2009
    61
    0
    Very nicely done. I made one using 7490 decade counters as well only mine is a 12 hour with seconds and I used a 74190 programmable decade counter, a 74191 programmable 4-bit counter, and a flip flop for the hours.
     
  8. mxabeles

    Active Member

    Apr 25, 2009
    182
    0
    hardcore man
     
Loading...