need help figuring out a sound Activated alarm

Discussion in 'The Projects Forum' started by logicmind, May 20, 2008.

  1. logicmind

    Thread Starter New Member

    May 20, 2008
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    http://ljs.academicdirect.org/A09/97_102_files/image004.gif

    above is the circuit, the latch(401) is actually a CD4013 dual flip flop. i am wondering from the amplfier's ouput what pin do u connect it to? the clock or the reset?
    also from the oscillator(CD4060) what pin do u connect the flasher and buzzer too?

    please help i am doing this for a scholl project. it's a matter of a A or an F..:(

    thankyou:)
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
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    Without a more legible schematic, it will be impossible to tell what is going on. :(
     
  3. logicmind

    Thread Starter New Member

    May 20, 2008
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    that's what am trying to figure out
     
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
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    From where does this circuit come?
     
  5. logicmind

    Thread Starter New Member

    May 20, 2008
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  6. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
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    Pulses from the amplifier go in on pin 3 (clock) of the F-F. Note they are resetting the F-F in alarm condition, and setting the F-F in normal condition. The "reset" switch therefore takes pin 6 (set)hi. This means the schematic is in error. The heavier black lines are Vcc, but are routed to the wrong position.

    I strongly suggest re-creating your own schematic based on the datasheets of the components. Post it here and we'll help you debug.

    You'll need to experiment with the output from the CD4060 to see which pins provide the best flashing and buzzing. I suggest starting with pin 1 or pin 15 driving the light, and pin 9 or pin7 for the buzzer. Move toward the center until you find what you like best.
     
  7. logicmind

    Thread Starter New Member

    May 20, 2008
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    thanks..i will start working on it..i will upload a schematic as soon as i finish
     
  8. logicmind

    Thread Starter New Member

    May 20, 2008
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    ok so here's the schematics. sorry i took so long..been bz with work. I already tried in on a breadboard without the reset switch and buzzer, just the led/flasher. but it didn't work. The amplifier section works, I don't know how to test the oscillator alone to see if it works, I even tried to connect the input from the oscillator straight to the amplifier bypassing the latch to see if it works but nothing. I i am thinking it's the oscillator, i used R1 = 100k R2 = 330 and C = 100pF, Should i try different value capacitors?

    by the way..anyone know where i can get multisim for free?

    here is the image
    [​IMG]
     
    Last edited: May 26, 2008
  9. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    1) All CMOS IC's must have all of their inputs tied to either Vdd or Vss; if left "floating" they will tend to cause unpredictable oscillations.

    2) This board does not advocate nor tolerate software piracy. Multisim is a commercial software package that is not free. Please refrain from making such inquiries here in the future.

    3) There are plenty of free circuit drawing packages out there, such as Tina-TI (from Texas Instrument's site), Linear Technology's LTSpice/SwitcherCad, and Eagle Layout Editor from Cadsoft amongst many others. Look in the Resources section.
     
  10. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    You have an extraneous 100uF capacitor. You must tie pin 4 of the LM3876 directly to ground. Ditto for pin 7 of the flip-flop.

    Resetting the flip-flop must be accomplished by switching a high to pin 6.

    There are other errors as well.

    I strongly suggest you study the datasheet for the CD4013.

    SgtWookie is correct.
     
  11. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    One fault that will cause the op-amp wont work at all is that you have a capacitor between pin 4 and ground. You must remove this capacitor, pin 4 must be connected directly to ground. Also the rest of the circuit suffers from serious problems. You have to read the components' datasheet carefully and redesign your circuit.
     
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