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"Simple" hour/minute binary clock?

Discussion in 'Electronic Components' started by [email protected], Oct 17, 2006.

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  1. Guest

    I've been all up and down Google for a couple hours now trying to find
    project instructions for a binary clock that displays just the simple
    hours/minutes but can't find it. All the projects I'm finding are BCD
    displays only, or display the time in a combination of four or five
    rows (including seconds). I was really looking to build one like a
    watch I saw, displaying hours on top and minutes below in two rows of

    8 4 2 1 (h)
    32 16 8 4 2 1 (m)

    Can anyone point me in the direction of a project like this?
  2. Tried ?
  3. Donald

    Donald Guest

    Are you looking to buy this unit as a kit.....
    schematics for a 74xx/40xx logic.....
    some microprocessor schematic.....

    By the looks of your description, you already have a spec.

    Looks like an opportunity to design your own.

    Pick a single chip controller with enough pins to drive the number of
    LEDs you want and start writting code.


  4. ISTR Scientific American had one which had wooden toggling displays.
  5. John Fields

    John Fields Guest

    Arguably the easiest way to do this in hardware would be to use a
    4020 to divide the 60Hz mains by 3600 to get 1 minute ticks, then to
    use those ticks as clocks to drive a 4040. The 4040 could drive
    low-current LEDs directly, and a decode at 60 minutes could be used
    to drive a 4024's clock input, which would give you binary hours out
    of the counter. Finally, a decode at 12:60 would reset everything to
    00:00 when the sequence would begin anew.

    Would you like a schematic?
  6. Guest

    12:60? Don't you mean 11:60?


  7. Popular Electronics, or Radio & Electronics magazines had a DIY
    project for this back in the '70s.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  8. No. You are at 12:59 and when you hit 12:60 you go to 1:00 instead.
  9. John Fields

    John Fields Guest

  10. John Fields

    John Fields Guest

  11. John Fields

    John Fields Guest


    Like Homer said, 12:60 will reset to 1:00. (Not 00:00 as I wrote
  12. "Homer brain beer well not work without"
  13. Guest

    John Fields wrote:
    Actually, yes! Please!

    My experience with electronics is somewhat limited - I've done some
    projects, but they've all been simple "hack it apart and change it"
    stuff, mostly on old video game systems (turning my NES into a portable
    system, making a light pen for my Commodore 64, etc.). I can read a
    schematic, and I'm sure any symbols I don't know can be found online.

    I've found a few projects which are close (ticking out time using an
    array of chips/crystals rather than using a BASIC stamp or other
    programmed chip to count off time, which I've done before & didn't
    like), but all of them are much more complex than what I'm looking for
    (a twelve-hour hours/minutes display in two rows), usually including
    dozens of LEDs to count out 24-hours and even seconds. I'd like to see
    if I can make one running off batteries rather than A/C, which means
    I'd need a crystal since I wouldn't have the 60Hz line.

    Like I said, though, my current experience is too limited to allow me
    to be creative, since I don't have much idea of where to start.
  14. I'd start from the back-end so you have something to look at.

    Get a 74HC4040 and hook up some LED's to the outputs.
    Ground the reset pin. feed any kind of square wave signal or pulses
    into the clock input. Watch the pretty LEDS count up.

    That will be straight binary counting, which can get a little tedious
    to decode.

    If you want BCD counting, with 8-4-2-1 lights for each decimal digit,
    then use a 4518, that's two decimal counters. But this will count up
    to 99, which is inconvenient.

    To get it to flip over at 59, you need to detect the "6" and reset with
    that, you can do with an AND gate, say a CD4081 or two gates of a

    Then to get your 1 cycle clock,I'd use another two 74HC4040s and a
    32,768 hz crystal.
    The crystal you can get to oscillate with one of the NAND gates in the
    74HC00. Google for "cmos crystal oscillator" for examples.

    Have fun!
  15. Guest

    Thanks for the suggestions. I don't think I was clear on what I wanted
    to build, though. Most of the projects I'm finding have a separate
    string of four binary numbers for each place:

    O O O X Tens of hours
    X X X X Ones of hours
    X X X X Tens of minutes
    X X X X Ones of minutes
    X X X X Tens of seconds
    X X X X Ones of seconds

    With the Os being empty spots where no LEDs are needed. What I wanted
    to make is similar to a wristwatch I found online, with just two rows
    of places 8, 4, 2, and 1, the top row being hours and the bottom being
    32, 16, 8, 4, 2, 1 for minutes. A link the image is here: watch square red led 250.jpg

    Maybe I'm just not clear on what you're explaining since I'm having
    trouble visualizing (like I said, I can read a schematic, but since I
    don't know much beyond that, I can't always "see" it when its spelled
  16. Rich Grise

    Rich Grise Guest

    Those guys do this:

    1 ppm clock ----- [BCD 0-59 counter] ----- [BCD 0-12 counter]
    10's 1's 10's 1's

    All you want is this:

    1 ppm clock ---- [Binary 0-59 counter] ---- [ binary 0-12 counter]
    5 bits binary 4 bits binary

    So, figure out how to get your 1Hz clock, then use three binary 4-bit
    counters, and some gating logic to get the minutes to wrap at 60
    and the hours to wrap at 12.

    Good Luck!
  17. John Fields

    John Fields Guest

    OK. I'll post a schematic to alt.binaries.schematics.electronic
    tomorrow, but since Google won't let you access binaries through
    Google Groups I'll email it to you as well.

    BTW, what battery voltage do you want to use?
  18. Hm... So your requirements are straight forward:
    - One X-tal ocsillator
    - One divider/counter to bring the oscillator frequency down to 1/60Hz
    - One divide by 60 (minutes) counter. All six ouputs to drive a LED and the
    rollover to clock the hour counter.
    - One divide by 12 or 24 (hours) counter, all four or five outputs to drive
    a LED.
    - All powered by battery.

    You can get almost every X-tal you want if only you are willing to pay for
    it. Cheapest ones I'm aware of are in the simple quarz clocks. They contain
    an oscillator and divider that gives a pulse every second alternating on two
    different outputs. Powered by a 1.5V battery you have a 1/2Hz clock. You
    only need a transistor the amplify the 1.5V pulse to the level required by
    the subsequent logic.

    As you want binary output you will need three binary counters. But as the
    range of the counters is not a power of two, you will need to reset them
    once they've counted to 29, 59 and 11(or 23) respectively. That means for
    the divide by 30 counter you should detect the value 29dec or 11101bin and
    reset the counter at the next clockpuls. IMHO best counters for this purpose
    are the classic 163 counters. Of course the CMOS version so CD40163B for
    instance. The divide by 30 counter requires two of then plus a four input
    NAND gate for the reset. Similar for the minutes counter. Decode 59dec or
    111011bin to reset the counter. If you want a 12 hour clock, you need only
    one CD40163B and decode 11dec or 1011bin for the reset.

    At 5V or 6V the CD40163b can provide the 1mA required to drive a low power
    LED. You can use buffers to increase this current but for a battery powered
    circuit I'd stick on the low power LEDs.

    petrus bitbyter
  19. Guest

    I really appreciate all your help on this! A big part of this project
    and a few other small ones I'm working on is to take my ability to read
    schematics and build something from them and actually learn what some
    of these components/circuits do so I can be a little more flexible and
    creative on some larger things I want to build down the road.

    Battery voltage doesn't matter, whatever will drive the circuit. I'd
    prefer to not use one of the huge 12v flashlight batteries though,
    since I wanted to hook a few batts up in parallel and mount clips to
    the circuitboard so the whole thing can be hung on a wall. 9v maybe?
    The chips will need a 5v I assume (everything I've been working with so
    far does). To drive those, I've cheated and used 5v power adaptors
    from Radioshack, but like I said I wanted this to be a self-contained

    Thanks again!
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