Making a circular clock

Discussion in 'The Projects Forum' started by FroceMaster, Jan 29, 2016.

  1. FroceMaster

    Thread Starter Member

    Jan 28, 2012
    Have this plan of making a clock with time, minut and second hand
    If i use 3-4 LED in series and use a transistor to drive it i will still have 180 outputs
    If i use 3-8 line driver and a ex 74hc375 or similar to drive it i would end up with 64 output. And then 3 sets of that. All driven by a microchip ex 16f1509
    Is that possible to do or do i have to total rethink everything

    Any hints

    Logic circuits and microchip is fine by me
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    Can you draw it out put so we can visualise what you are doing?
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
    12 drivers for hours?
    60 drivers for minuets ?
    60 LED's around rim for seconds ?
    Take hours, needs 12 control pins so to reduce count use 74HC154 16 step stepper requiring only 4 address pins. 74HC family uses 5 to 6V VDD, so use a buffer ( 74FCT244ATP, 8 stages or ULN family ) to drive LED's in parallel with a resistor for ea. LED ? 4- 74HC154's for min. & sec. 4 address lines & 4 control lines for ?
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    There are many LED clock schematics on the innergoogle, and some of them are very similar to your project.

  5. FroceMaster

    Thread Starter Member

    Jan 28, 2012
    oki, can you give me an example ?
  6. absf

    Senior Member

    Dec 29, 2010
    I built this one a couple months ago and it's cool...:)

  7. FroceMaster

    Thread Starter Member

    Jan 28, 2012
    More like this,
    Where the time on this is "15:10:00" "Watch.png"

    The 'Problem" is that i would have 180 outputs to control.

    Any hint on doing that ?
    i have planes to do it like this "first lay.png"
    i know i miss a lot on the controls, but i think you get the big Picture on how..
  8. hp1729

    Well-Known Member

    Nov 23, 2015
    24 hour clock? 15:10 is 3:10 PM.

    I gave some thought to such clocks but simplified it down to just 12 positions. 12:00, 12:05, 12:10 etc. A lot fewer LEDs.
  9. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    It's not really a big problem just very time consuming to build, you can do it all with shift registers, a bit of logic and a 1 second timebase, the PIC is not necessary. Divide the clock into 3 concentric rings with hours in the middle (12 outputs), then minutes (60 outputs), then seconds (60 outputs). If you use open-collector outputs (which you probably will) and "steering" diodes, you can overlap the "hands".
    Last edited: Jan 30, 2016