hard of hearing help

Thread Starter

Gompers

Joined Feb 21, 2007
18
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.
 

Gadget

Joined Jan 10, 2006
614
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.
 

Thread Starter

Gompers

Joined Feb 21, 2007
18
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??? .
 

Gadget

Joined Jan 10, 2006
614
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).
 

Xray

Joined Nov 21, 2004
58
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.
 

Thread Starter

Gompers

Joined Feb 21, 2007
18
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
 

bloguetronica

Joined Apr 27, 2007
1,372
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.
Strange! Higher frequencies are more prone to cause ear damage.
 

Gadget

Joined Jan 10, 2006
614
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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