You don't want an amplifier, you want a sound activated switch which throws the load across the batteries when the mic output exceeds a threshold corresponding to the appropriate sound level. Of course a 555 type of device configured as a retriggerable monostable, activating the load for a few seconds on each threshold crossing, is what is needed.
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He is a solution that would use the least parts yet do what you want to do on 3 Volts. It uses an 8 pin microprocessor such as the PIC12F510 or equivalent. This 8 pin DIP is the TOTAL electronics except for a cap or two, a resistor or two, a mic and an adjustment pot.
The processor has a built in analog to digital converter. The input of this A/D is directly connected trough a cap to an electret mic., the signal source. The A/D continuously samples the microphone output and digitizes it to a 10bit word. Additional amplification is probably not necessary with this type of mic depending on the loudness. This value is constantly being updated in memory and compared with a reference byte that corresponds to the loudness threshold you want to trigger on. This reference can also be put into the A/D as an analog voltage from a pot if you want it adjustable.
When the peak audio exceeds the level of the reference, an output is generated on two or more digital ports of the processor. These output ports can source or sink 25 mA. so, two or three in parallel will drive the 50 mA you require to run a vibrator.
An internal timer in the processor keeps the output port "on" for several seconds upon each trigger. This "buzz" time can be anything you desire.
This is a simple single chip solution using an 8 pin part that cost less than a dollar, but, it does require some simple processor code development if you want to tackle it.
I like microcontrollers, but for a task which requires a comparator and a monoflop, only (and maybe an amplifier), this looks like a more expensive and too complicated solution (because you have to program it), compared to just a quad op-amp.
Yeah, but they were the same bunch that raised Sloman.
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two,
You can't drive 50 mA with a quad op amp and you'll have a hell of a time getting it to run on three volts. Furthermore, there is whole hand full of other parts required.
Is $0.50 expensive? Yes, you do have to code or have someone do it for you.
According to the headers it is.
Maynard A. Philbrook, KA1LPA = "Jamie"
** Any post from a demented, code scribbling, radio ham like YOU = a fool's answer.FOAD you ass.
..... Phil
Is that all you got?
You seem to be coming up short lately or is that the story of your life?
The meds must be starting to take effect at long last - he used to be able to rant a whole page.
My money is on Carpal Tunnel Syndrome and stiff keyboard springs.
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If you have broadband, your ISP may have a NNTP news server included in your account:
Sporadic E is the Earth's aluminum foil beanie for the 'global warming' sheep.
Or he got really incoherent and confused a toaster for his keyboard!
Rumor has it that he plays with his toasters a lot more than his keyboard.
Count '>'s - you'll see that somebody got dropped upthread.
Phil may be an insufferable boor, but I've never seen him snip attribution.
Cheers! Rich
What newsreader? Is it broken?
I count five posts just in this sub-thread, not even counting branches.
Cheers! Rich
Which could lead to the first case of a STD transmitted by a flying toaster.
--
If you have broadband, your ISP may have a NNTP news server included in your account:
Sporadic E is the Earth's aluminum foil beanie for the 'global warming' sheep.
What became of your pal Genome?
If every interaction that you have with others ends up in conflict, you may wish to try to figure out what the common factor in those interaction is.
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