digital timer cum 2*7 segment display along with buzzer

Discussion in 'General Electronics Chat' started by yashovardhan, Oct 8, 2012.

  1. yashovardhan

    Thread Starter New Member

    Oct 8, 2012
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    i am implementing a timer circuit along with buzzer. i have cd 40110 ic in cascade format for 7 segment display.
    for driving the ic i used 555 astable clock for one second.
    so that after each one second the counter and display increments now i want to a veriable time period circuit so that after each N seconds, the ic cd40110 resets and start to count again from zero , along with a buzzer will remain on for 4 seconds.

    how to do this??????????


    in summery i need a buzzer cum display for each N seconds.
    after N seconds a buzzer will sound for 4 seconds
    how to do this by ic cd40110.

    the value of N can vary by 20 to 55 seconds


    ps i cant use any microcontroller and any programmable ic
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    For that you need a comparator(s) Most common are 4 bits comparators. But two may be used to create one 8 bit. The buzzer can be controlled by a one-shot timer. For more info use your friend google. I suggest searching for one-shot timer and 4 bit comparator. That should give you something to work on
     
  3. yashovardhan

    Thread Starter New Member

    Oct 8, 2012
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    0
    thanks for the reply
    i am working on cascading the two ics with led displays and want to down count the time by its borrow pin. the counter comes from the value to 00 and reset to its value again at the same moment i cant on my buzzer by one shot timer.

    i need for assistance in presetting the value on display.and to change the value manually.

    please help
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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  5. elec_mech

    Senior Member

    Nov 12, 2008
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    The 40110 cannot be preset. Are you confined to the 40110? It is a great IC, but for your application a pair of 4510 and 4511 (or 4543) ICs would do the trick. The 4510 takes a clock signal and converts it to BCD. The 4511 or 4543 accept BCD and convert it to drive a 7-segment display.

    The 4510 is presettable and you can change it on the fly using pull-down resistors and a BCD switch for each IC on the preset inputs. You can also use an AND gate or a pair of diodes to form an AND gate and reset the display whenever a certain value is reached.
     
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