Here's how all digital clocks are made!

Discussion in 'Lounge' started by The_YongGrand, Oct 1, 2008.

  1. The_YongGrand

    The_YongGrand Just Started

    Of course, you've seen it every day, every place, and even in your microwave, toasters, ovens, televisions, toys and stuff like that. All of them featuring a digital clock!

    Even your computer tells you the time!

    So, you must be wondering how the hell is this thing made up? Normal analog clocks are all made by 'gears' and quartz crystals (to generate 1-second pulses), but it's different in digital clocks! :mrgreen:

    Ok - there's a simple block diagram of it:

    Pulse Generator (Wave-Shaping circuit, Oscillator, or Astable Multivibrator system) to generate 1-sec pulses -> divide-by-60 counter (second portion for it to count 0-59 before adding one to the minute) -> divide-by-60 counter (minutes portion) and finally, some gating circuitry for the hours (0 - 12).

    Every of these counters are interfaced to seven-segment display drivers.

    It seems complex, but I will have to explain more in layman terms!

    Here's the pic: (only the seconds part is shown, I've done the minutes part but I dunno where the hell I shoved that thing!)

    Edit: You might need uh like 6-counters and 6 display drivers (TTL 7490 and TTL 7447) for these (and an AND gate too!), along with a huge supply of 330 ohms resistors, and those 7-seg displays. And also, many wirings! I prefer not to use TTL because I need a darn voltage regulator to bring it to a +5V which is tedious.

    And, now, all those digital clocks isn't made up of many chips in a huge interconnected breadboard. It's now simplified to LSI (Large Scale Integration) circuits and they even have calendars and alarm clocks!! :haha:

    Attached Files:

    Last edited: Oct 1, 2008
    1 person likes this.
  2. Trinity

    Trinity Little Kiki Staff Member

    Nice breadboard!!!:wave:
  3. The_YongGrand

    The_YongGrand Just Started

    Yeah thanks!

    Btw, it is purchased from an e-tailer from a different state in my country. The breadboard is detachable, even the horizontal conductors are detachable.

    And in my college lab they used the same breadboard too. Except for the burn marks on the divider because of clumsy students burnt off ICs too long onto it.

    Besides digital clocks, these counters can be interfaced to do something else... very exciting!

    You can make an egg timer (up to 60 second), or a uh... Roulette and even a digital dice. You need the 555 and with some knowledge of wiring it for pulse generation to drive them. :mrgreen:
  4. Chai

    Chai Administrator Staff Member

    Haven't used a breadboard for a long time...
  5. lee_what2004

    lee_what2004 Just Started

    Those cable really looks messy.
    I only know how to make clock generator. :haha:
  6. The_YongGrand

    The_YongGrand Just Started

    Yeah, the cables are damn messy. That's why LSI are introduced. Now, all of these counters + gates are shoved into just one small die and there goes a small digital clock! :D
  7. Lacus

    Lacus Newbie

    cool 1..finally i saw the picture appear in the forums instead :p..
  8. Zenphic

    Zenphic Newbie

    Hahah, so messy. Looks like you had a good time :p

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