Extending a momentary tone

Discussion in 'The Projects Forum' started by shezza, Mar 31, 2014.

  1. shezza

    Thread Starter Member

    Mar 19, 2014
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    Hi all,

    I wanted to take a 3.5v momentary signal and extend its duration or at least use it as a marker to activate another source of voltage. The single beep is not sufficient on the Chamberlain CWA2000, too easy to miss... So I want to make it louder and longer.

    Thanks
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
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    What is the nature of the triggering signal?

    A monostable multivibrator chimes to mind...
     
  3. #12

    Expert

    Nov 30, 2010
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    It seems that this can be accomplished. What is your level of being able to design or build electronic gadgets?

    PS, I'm posting the location of a similar thread so the helpers can see that another person accomplished this task.

    http://forum.allaboutcircuits.com/showthread.php?t=88877
     
    Last edited: Mar 31, 2014
  4. shezza

    Thread Starter Member

    Mar 19, 2014
    45
    0
    Could you explain the basic operation of this?

    I was already looking at that... but I need it to switch for a period of time. That only seems to operate it as momentary as the bell chimes.
    So a timed switch set off by the momentary signal.
    I have pretty basic knowledge. I understand the very basics. I do all the wiring on my car, I understand signal wires, switches, 4/5 pin relays, I have built custom led arrays. Though I havent used transistors, capacitors or ICs.
     
    Last edited: Mar 31, 2014
  5. #12

    Expert

    Nov 30, 2010
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    A monostable multivibrator is geek speak for, "oscillator". Apparently there is an audio frequency oscillator in the "Alert System" that drives the speaker to sound like a bell chime. You need to tap into that circuit to get some signal that will trigger another device that runs longer when it is activated. You also need to find or make some voltage to run the new sound device.

    If you can get the speaker driver to turn a transistor on, that can trigger an LM556 timer. The first section will set the amount of time you want the audio to be on and the second section will make the audio. That particular chip can run a small speaker.
     
  6. tshuck

    Well-Known Member

    Oct 18, 2012
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    As #12 suggested, if you are attempting to make an add-on, you would need to have a device triggered by the standard audio output line (the monostable multivibrator aka one-shot), which would enable an audio oscillator (the 556), which generates the audio signal that the speaker will emit.

    If you can get your hands on a schematic of the thing, it may be possible to modify the original circuit to accomplish this...
     
  7. #12

    Expert

    Nov 30, 2010
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    Oh, darn. tshuck caught me making a mistake. Monostable doesn't continue oscillating.
     
  8. tshuck

    Well-Known Member

    Oct 18, 2012
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    I did? I thought you were talking about using half of the 556 for the monostable and the other as the oscillator...
     
  9. #12

    Expert

    Nov 30, 2010
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    There's the mistake.

    Yes, I was talking about using a 556 for a one-shot and an oscillator, but the first sentence was misleading.
     
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