Building a CMOS clock on a breadboard

If you’re going to learn digital logic, why not aim high? That’s what [Easton] and his friend did when they built a clock using only 4000-series logic chips. On a breadboard, no less.

For a 1 Hz clock, [Easton] and his friend used a 4060 counter paired with a flip flop. This counts off 59 seconds until, with the help of an AND gate, the seconds counter rolls over to zero. After repeating that again for the minutes and building a similar circuit for the hour, and [Easton] had a working 4000-series 24-hour clock.

The breadboard clock may not be the prettiest thing, or a textbook example of how to prototype circuits,  but that was fixed with [Easton]‘s friend’s PCB layout of a 12-hour clock. We couldn’t find any pics of this, but we’re sure it’s awesome and a great way to learn about logic and design.

Comments

  1. DM says:

    One of my first electronic projects back in college, though I kept expanding into a “rat’s nest” alarm clock. It’s a great project and was a lot of fun.

  2. dbear says:

    This was a common project when I was teaching digital electronics. I used to give them a project of their own choice as the final lab grade. Every semester someone would do this. It is a great way to learn digital. Nowadays students do stuff like this on a SPICE simulator. Just not the same.

  3. justice099 says:

    Like the others, had to do this in college as well. I built mine on protoboard and did all point to point wiring, though.

  4. dbear says:

    BTW Try diagnosing a student’s clock when it looks like this and they are about to give up in frustration. Really builds the troubleshooting muscles.

    And I have seen worse.

  5. Destate9 says:

    Yeah, did this in a high school class, but always impressive. Taking this on as a personal learning project would take mad cajones

  6. M4CGYV3R says:

    Nest of wires?

    Nothing a little gaffer tape can’t hide.

  7. mshieh says:

    The “clock I made from logic gates back in college (2009) is still running at my parent’s house.

    Learned a lot from it and finally understood how to read timing diagrams which were really useful when dealing with communication protocols.

    • mshieh says:
      • Alex says:

        That’s a damn good looking clock! Excellent documentation, too. My only criticism is that I don’t like blue LEDs, but that one’s entirely personal.

      • mshieh says:

        Thanks for the comments. I’m in medical school now and rarely have the time to write such articles anymore so I tend to cling to it from time to time. lol. Blue is my favorite color and that’s why I chose it but yeah I can see it’s not a color that one would want to be looking at during the night. I would have probably went for green if I had to do it over.

      • dghretiueht says:

        Very very nice work.

        One request regarding the documentation: It would be nice if the documenation to your clock project could be downloaded as a whole, instead of needing to download the individual pages one by one, or downloading your entire website with a site scraper. One file containing an archive of the entire project in html format (including images) would be perfect. A single PDF would be good too.

  8. JulsPower says:

    school work

    but teacher rules with breadboard is: if my finger can get under the wires, wires will come off

  9. NewCommentor1283 says:

    good wire porn JK

    good work, he says he learned the whole way through… to make a clock. i learned BEFORE trying to do a clock… but learning it WHILE building it MUST have been very, _VERY_ frustrating!

    after i got seconds and minutes(edit: i think only 1 digit of minutes) i said it was enough! ran out of breadboard space but most importantly sanity!

    • barryronaldo says:

      I have to agree that it looks pretty daunting. I’m a tinkerer without any schooling, so my breadboard patience can wear thin as well. I do think this would be a fun project to do the silicone brick housing for. Glad someone else had the same reaction lol.

      /kudos to the builder

  10. kamarov says:

    I didn’t think my submission went through!

    This is terrible wiring, as other have said. I meant to wire it quickly so we could move on to making the PCB. Of course, this didn’t turn out since I’m out of school now.

    My friend’s PCB didn’t quite work after he etched it, since we could only print single-sided PCBs. This added to our frustration since we had to manually route everything, as opposed to DesignSpark routing everything automatically.

    • Destate9 says:

      Laen PCB, dog. $5 a square inch and you get three copies of the board. I’d say you should spring for a professionally made board on this one because having two sides would make this soooooo much easier.

  11. Oliver Heaviside says:

    There’s nothing wrong with this wiring. See the bread board? It means that it’s a lash-up to see if it works. That’s fine.

    I recently saw a bizarre vacuum tube breadboard nightmare at a yard sale that appeared to be some sort of counter, but as it had only neon indicator lights, I passed. The burnt and oozing electrolytics didn’t make a very compelling “buy me” argument.

    I do miss blinky boxes. I once wired up a hundred and thirty or more leds using counters and gates to make random repeating patterns. You put a bit of patterned plexiglass diffuser over that and you have a very interesting project.

    Add a couple of band-pass filters to grab audio signal, and then drive the counters or gates from them through a comparator – it’s magic!

  12. Dr. James says:

    Yep, did this as a freshman EE major looong ago — but with TTL logic. It’s a very good project to help learn digital logic, and I recommend it to anyone who has not gone down this path. Regarding the 1 HZ clock, that should have been generated by counting AC powerline cycles, rolling over every 60 counts to get that 1 HZ clock. A build like this will teach why decoupling caps exist. It sure brought back some nice memories. Thanks!

    • NewCommentor1283 says:

      i “lol”d at “…why decoupling caps exist” muahahahahah

      if you dont know why this is so funny your going to have a “fun” time replicating this from scratch with no schematics!
      (unless your an impulsive capacitor user;))

  13. Willy says:

    I built something similar for one of my classes, this makes me want to find and see if it still works

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