Clock sans-microcontroller

This clock requires no microcontroller. It’s actually a digital logic counter that functions as a timepiece. [BlackCow] used six decade counters to track seconds, minutes, and hours. The output is displayed on four 7-segment digits using BCD-7-segment decoders that you can learn about in our binary encoded decimal post. The actual timekeeping is done by a quartz clock circuit he pulled from a Mickey Mouse clock. This would be a perfect circuit to build in a digital logic simulator, just follow the schematic and learn as you go.


  1. dickens says:

    my old digital watch required no microcontroller either.

  2. Tom says:

    Most Nixie clocks also don’t require a micro.

  3. Freax says:

    @Tom: “most”? At the moment I can only think of 2 projects without a mc… more examples? *curious

  4. Colin says:

    I remember making one of these in electronics class. Very simple design, but very fun to mess with.

  5. Paul Potter says:

    That’s really good. Nice and old school design.

  6. Ulrich Lukas says:

    That’s my version ;-)

    OK, it’s not a clock, but a 4-digit decimal up/down counter using CMOS 4000 logic.
    And my design even uses battery-backup to save the value in CMOS, so there really are the same design considerations as for a clock.

  7. jc says:

    Trying to figure out why this post is post-worthy.

    Someone builds a circuit out of discreet parts and it’s all like “Wow! Look at this! This is amazing!”.

    Dudes, we did this *all* the damn time back in the 70’s, 80’s, and 90’s. Sure, point-to-point and wire-wrap isn’t as popular as it used to be, what with board layouts being so cheap.

    I point-to-point stuff all the time, usually before I lay out a board, or if it’s a one-off.

    This is not to disparage the effort of the guy who built the clock. No beef with him, I love clocks. But it’s not post-worthy, hack-a-day. Just like neither is wiring up a 2-way light switch in your living room.

    <end-of-old-is-not-really-new-rant />

  8. anon says:

    This is not a hack, it’s 1st year digital logic.

  9. Dude says:

    Oh no, here we go again.

  10. Ulrich Lukas says:

    Oh come on. Yesterday’s technology applied, where you could achieve the same functionality much easier with today’s technology – for me, that’s a hack.

  11. JB says:

    Not to put down the effort put into this project, but I’ll have to agree with the others that said this is 1st year digital logic, not a hack.

    Nice to see someone still using “old” hardware. If you are impressed with that, then you should take a look at this one

  12. Mike says:

    Has anyone seen or built an analog clock? By that I mean one that doesn’t use any digital circuitry.

    I’ve had this idea for a clock that uses capacitors in series and each capacitor is hooked to an analog meter that shows the time (hours, minutes, maybe seconds) but not gotten around to building it.

  13. steve says:

    I love it! looks like a 555 for the clock and maybe some shift registers.

  14. Robert Langdon says:

    Oh, my God, my mouse clock¡¡¡


  15. sgf says:

    Aw. I think people are being a little harsh. Sure, it’s simple. I think that’s the point. If we’re bored with Arduino overkill, at least allow a simple comprehensible example of uC-free design to show newbies the alternatives.

    The fact that almost anyone could do this is kinda the reason for the post – hopefully it’ll inspire a few more inexperienced people to have a go!

    (Not to say hack-a-day should be /full/ of beginners’ articles, but the occasional entry-level Arduino-free post makes me happy :p )

  16. Jujubes says:

    If it’s worth mentioning, everyone in my electronics engineering program had to do this project in a digital-logic class.. In our FIRST year.

  17. anon says:

    Incessant rabble about the quality of hack-a-day aside, you people fail to remember hack-a-day is a collection of like-minded people with varying levels of knowledge and skill. Even though some of the posts may insult your intelligence, they could spawn the love of electronics and hacking for a new generation of people, people who need to start out with these types of projects so they may appreciate just how much simplification is done when selecting an Arduino. So while I’m not really raging about the comments, I will ask you to have a nice cup of shut the fuck up.

  18. beautiful wiring there

  19. bcoggs says:

    The ultimate all-tube descrete logic nixie clock:

  20. Shawn says:

    Anyone up for a ‘relay clock’? Something along the lines of this computer:

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