digital clock schematic request

Discussion in 'General Electronics Chat' started by lokeycmos, Jul 11, 2011.

  1. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    ive searched and searched looking for a cut and dry circuit to build . i have moderate digital experience. i found some nice circuits based on pics, but i dont have the tools to program my own. im looking for 12 hour format with seconds with the smallest amount of ICs as possible. i want to breadboard it and hang it from the wall. anyone have a suggestion for a schem with these features?
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    TBayBoy likes this.
  3. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    Here's a couple of ideas.

    This is 24 hour format, but gives a starting point.
    Rolling over from 12:59:59 to 1:00:00 requires more logic than
    a 24 hour format.

    Beautiful clock


    This is a 00-59 counter portion only, merely one building block.
    00-59 counter

    These are presented as found, not tested.

    The common theme with these two happened to be
    the use of the CD4026 I.C. There are others out there.

    If I run across a 12 hour format w/o microcontroller I'll
    post link.

    Edit:

    Maybe 12 hour format.
    uses 74HCxxxx I.C.'s but could probably substitute
    4000 series if you prefer.

    Look here
     
    Last edited: Jul 11, 2011
    TBayBoy likes this.
  4. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Pencil showed me the Digital Watch link. It is in 12Hr format.
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    You did say "smallest amount of ICs"... There are dedicated "clock ICs" as used on most of the older (1980's and 1990's) alarm clocks etc. These are a single IC that will act as the clock and drive the display.

    I think these days making a clock without a microcontroller is like those people that make their own V8 engine on a lathe... It's an interesting and possibly rewarding hobby but really you have to question is it the best way to go about getting an engine? ;)
     
  6. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    I have used the NTE2061 digital clock IC. It is still available from Mouser for about $10.00. The digit drive is not mutiplexed so a multiplexed display can't be used. I still have the PCB layout and the schematic if that would be helpful.
     
  7. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    Here is what I have

    Digital clock notes.

    The picture of the clock shows large digits. The digits are 4” tall and the one that indicates tens of minutes has been inverted so that the dot can be used the hours 1 digit for the colon. As a result the inverted minute’s digit was rewired so that all the segements light up as normal. The schematic shows a 9V battery back up circuit. The large displays have approximately 8 LED’s per segement, that is why the ULN2004 drivers were used. All the displays are common anode, and a separate regulator was used to control the voltage to them. The circuit with the LM358 has a photo sensor to detect darkness and decrease the intensity of the displays.
    I chose to use a crystal 2.4576Mhz as the clock and divide it down with CMOS IC’s. Once the clock was built I adjusted the value of the two capacitors connected to the crystal while measuring the frequency on a frequency counter to get the crystal right on frequency. In several years the time is only off a few seconds.
    The circuit board is shown from the top looking thru the board. The board was done with + sensitized board, exposed, developed and then drilled. The board to 1X1 scale.

    I will help as much as possible with anyone who wishes to duplicate this project
     
  8. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    i am totally doing it!! couple questions, where does pin 9 on the cd4060 go? pin 38 on the main ic says 12/24. does that mean i can toggle back and forth between 12 and 24 hour format?
     
  9. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    Pin 9 was used as a test point to measure the clock frequency.
    Pin 38 of the clock chip as shown is for 24 hour time, leaving pin 38 unconnected will cause the clock to be 12 hours. Putting a spst switch to connect pin 38 to the Vcc line with enable you to toggle between 12 and 24 hour operation.
     
  10. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    is there an equivelant part number? digikey doesnt carry NTE part numbers
     
  11. k7elp60

    Senior Member

    Nov 4, 2008
    478
    69
    Actually the NTE2061 is a substite for the National semiconductor MM5316. Mouser, MCM electronics and Allied Electronics have stock the last time I checked. Why don't you buy it from one of those?
     
  12. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7

    digikey has every part ive ever needed. it nice to make 1 big order than making multiple orders from different vendors
     
  13. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7


    how do i print out the PCB in 1:1 ratio? ive tried printing it several different ways and always comes out way to big!! i just ordered the parts and cant wait to get this going!
     
  14. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    What software are you using to generate the basic print?

    I use PCB express, then print out using Printforge PDF (google it). There are settings to get 600 DPI, the native format for most laser printers. I use Gimp to actually print it to the printer, but again, there are internal settings. To manipulate the image I still M/S Paint, but Paint does not have the ability to print 600DPI like Gimp does.

    You just have to search for the settings as far as I know.
     
  15. Dr_Ram

    New Member

    Sep 14, 2011
    7
    2
    Hmmm, I just finished with a project that uses all of 3 everyday logic ICs (apart from the nixie tube drivers) to create a flexible 2-digit serially cascadable counter module that can count from 0-99, 0-23, 1-12 or 0-60 by setting 3 jumper switches and fits on 7 square inches. I thought it would be a nice "universal counter" module for a clock or frequency counter. Perhaps offer it as a kit. Did I just create a V8 on a lathe :)?

    Cheers - Ram
     
  16. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    sorry, i gave you the wrong idea. if you look at post #7 by k7elp60, he posted a PCB layout as a picture attachment. this attachment is not printing to scale. im using the toner transfer method to make my own PCB.
     
  17. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    i breadboarded the circuit k7elp60 posted using the nte2061. it works great as a 24 hour clock, but i cant seem to be able to get 12 hour mode out of it. apparently ur supossed to disconnect pin 38 to get 12 hour.when i do that it counts to 30 hours and resets from there. any hellp or advice pls??
     
  18. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Absolutely! And you just took electronics back about 30 years, I remember 2 digit and 3 digit counter modules as popular kits in the late '70's.

    Don't forget you need 2 kits to make a 4-digit clock (and that's IF you already have a 1 minute pulse), a total of 14 sq inches. A single PIC chip of 0.2 sq inches can do the whole clock... ;)

    Anyway I'm just teasing you, it can be a lot of fun making a V8 on a lathe. And people even buy kits for that sort of thing too. :)

    To lokeyCMOS, the schematic shows the "12/24 sel" pin on pin 38. Try connecting that input to 5v or 0v, through a 1k resistor.
     
    Last edited: Sep 21, 2011
  19. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    i figured it out. if you look at the schematic posted by k7elp60 the 10's hour driver ic is hard wired for 24 hour in addition to the 24 hour jumper. so i had to disconnect a couple pins going into the driver ic in addition to the jumper.
     
Loading...