hard of hearing help

Discussion in 'General Electronics Chat' started by Gompers, Nov 17, 2007.

  1. Gompers

    Thread Starter Member

    Feb 21, 2007
    18
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    Thinking of a simple method to amplify the beeping sound of my microwave's timer. I can barely hear it unless I'm inside along with the pizza.
    Perhaps, a mike hooked up to amp and remote speaker ??

    Radio Shack components??? Thanx in advance. Ed from Ct.
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Replace the beeper with a relay. Use the relay to switch power to a horn.
     
  3. Gadget

    Distinguished Member

    Jan 10, 2006
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    Air horns I assume....

    Often (as in My case) you tend to go deaf to higher frequencies, while the lower frequencies are still fine. Perhaps instead of amplifying the sound, you get a beeper (or modify the original circuit depending on whether it is a self contained beeper, or just a sounder) so that the beep frequency is much lower.
     
  4. Gompers

    Thread Starter Member

    Feb 21, 2007
    18
    0
    Gadget and thing maker, Thanx for your replies. I had the whole unit apart but, couldn't access the sounder/beeper . Hence i want to hook up a stand alone receiver/amplifier/speaker. Karioke??? .
     
  5. Gadget

    Distinguished Member

    Jan 10, 2006
    613
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    Without access to the beeper, and a lack of a circuit diagram that could be a tad tricky.
    Most Microwave timers use a dedicated Micro, and the sounder is driven by a buffered squarewave output from that same micro.


    Warning.... Playing around inside a microwave can be very hazardous to health. The HV capacitor can potentually have in excess of 2.5 KV across it, as can the Magneton..(most have bleed resistors that still work though).
     
  6. Xray

    Well-Known Member

    Nov 21, 2004
    58
    1
    A very simple method to flag you when the microwave is done is to monitor the AC current going into the oven. You can rig up a simple circuit between the oven and the AC line, that uses maybe a high current AC relay. The relay coil, with only a few heavy turns of wire, and normally closed contacts, would energize when the oven is drawing current (typically 7 to 10 Amps depending on the oven's power). When the oven times out, the current draw would drop to nearly zero and the relay contacts would close, setting off your own very loud beeper or flashing light!

    I have one warning about this system. It will not work properly if you use the oven's "defrost" mode, or any other mode where the power to the magnitron cycles on and off during the cooking period.
     
  7. Gompers

    Thread Starter Member

    Feb 21, 2007
    18
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    Excellent Xray, I can parallel the drive motor with a 120v relay. When the motor is energized, so will be the relay coil and with a locking circuits (via the second set of contacts.)normally open contacts contacts will connect to a pizieo buzzer . A momentary switch will interrupt the locking circuit to mute the buzzer. . Thanx a bunch Gompers
     
  8. Gadget

    Distinguished Member

    Jan 10, 2006
    613
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    Yup, that should work. Thinking outside my square were ya..?? Good on ya, thats what it's all about.
     
  9. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    Strange! Higher frequencies are more prone to cause ear damage.
     
  10. Gadget

    Distinguished Member

    Jan 10, 2006
    613
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    You are quite correct, and they damage those high frequency receptors in the ear that they torment, which is why most people tend to go deaf at those same high frequencies....
     
  11. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    So, that's why the elders are less sensible to high frequencies.
     
  12. Gadget

    Distinguished Member

    Jan 10, 2006
    613
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    Yup, B's C's D's E's G's P's T's V's Z's all end up sounding the same without the high frequency portion. And the High hats on the drum kit go silent...(my experiance anyway)
     
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