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PICList Thread
'Little PIC project problem....HELP'
1998\08\25@155833 by Alessandro Marzini

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I see a scheme to connect a microphone to PIC to wake up PIC from a sleep
instruction after a sound reach the microphone. I try a ceramic microphone
(which one used in the phone) and a speaker as a Microphone but nothing work.
Because the project is little and easy for teacher like you ;-) Can you tell
me which microphone, which capacitor, which diode, wich resistor to use in
this project and which PIC code (PIC16c84) to use?

Thank you very much, sorry for my English and for my be beginner :-|

Bye.

Attachment converted: wonderland:Vetrinfranti.JPG (JPEG/JVWR) (00014D13)

1998\08\25@161704 by Ryan Pogge

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a microphone from a phone should work....
looks like any small switching type diode will work, 47k 1/4 watt resistor
and a 100 nf cap... thats .01 uf??
someone correct me if thats wrong.


{Original Message removed}

1998\08\25@165206 by John Shreffler

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-----Original Message-----
From:   Ryan Pogge [SMTP:spam_OUTpoggeTakeThisOuTspamSHORE.INTERCOM.NET]
Sent:   Tuesday, August 25, 1998 4:18 PM
To:     .....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU
Subject:        Re: Little PIC project problem....HELP

a microphone from a phone should work....
looks like any small switching type diode will work, 47k 1/4 watt resistor
and a 100 nf cap... thats .01 uf??
someone correct me if thats wrong.


-----Original Message-----
From: Alessandro Marzini <a.marzinispamKILLspamIOL.IT>
To: .....PICLISTKILLspamspam.....MITVMA.MIT.EDU <EraseMEPICLISTspam_OUTspamTakeThisOuTMITVMA.MIT.EDU>
Date: Tuesday, August 25, 1998 3:58 PM
Subject: Little PIC project problem....HELP


>HI!
>
>I see a scheme to connect a microphone to PIC to wake up PIC from a sleep
>instruction after a sound reach the microphone. I try a ceramic microphone
>(which one used in the phone) and a speaker as a Microphone but nothing
work.
>Because the project is little and easy for teacher like you ;-) Can you
tell
>me which microphone, which capacitor, which diode, wich resistor to use in
>this project and which PIC code (PIC16c84) to use?
>
>Thank you very much, sorry for my English and for my be beginner :-|
>
>Bye.


1998\08\25@185016 by paulb

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Alessandro Marzini wrote:

> I see a scheme to connect a microphone to PIC to wake up PIC from a
> sleep instruction after a sound reach the microphone.

 You *definitely* don't want the microphone connected to the MCLR
input as the noise, whatever it is, would continue to reset the PIC
again and again, preventing it operating at all.  Use the RB0 interrupt
line to wake from sleep.

 A critically-biased high-gain transistor stage (few megohms base
resistor, collector load say 33k or provided by the weak pull-up in the
PIC (perhaps not or RB0 then) with capacitive coupling to the electret
should work.  Note however that the electret bias resistor is about 3K
and the electret does therefore pull a milliamp or so.

 Electret?  Well, I daresay a piezo disc would work with a single-
transistor amplifier.
--
 Cheers,
       Paul B.

1998\08\26@010426 by netquake

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100 nf = 100*10E-9 f . 0.01 uf = 0.01*10E-6 f
 "    =  10*10E-8   .    "    =   0.1*10E-7 f
 "    =   1*10E-7   .    "    =      1*10E-8 f
      =  0.1*10E-6  .    "    =       10*10E-9 f

So 100nf are 0.1uf and 0.01uf are 10nf
(I guess! ;-)


P.D: does anybody knows of a shareware/freeware program
that handles .pcb files (Tango,etc)?
----------
> Ryan Pogge <poggespamspam_OUTSHORE.INTERCOM.NET>
> @spam@PICLISTKILLspamspamMITVMA.MIT.EDU
> Re: Little PIC project problem....HELP
> 25 de Aug 1998 17:18
>
> a microphone from a phone should work....
> looks like any small switching type diode will work, 47k 1/4 watt
resistor
> and a 100 nf cap... thats .01 uf??
> someone correct me if thats wrong.
>
>
> {Original Message removed}

1998\08\26@030328 by Nigel Goodwin

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In message <KILLspam511.541T2425T9083445KILLspamspamiol.it>, Alessandro Marzini
<RemoveMEa.marziniTakeThisOuTspamIOL.IT> writes
>HI!
>
>I see a scheme to connect a microphone to PIC to wake up PIC from a sleep
>instruction after a sound reach the microphone. I try a ceramic microphone
>(which one used in the phone) and a speaker as a Microphone but nothing work.
>Because the project is little and easy for teacher like you ;-) Can you tell
>me which microphone, which capacitor, which diode, wich resistor to use in
>this project and which PIC code (PIC16c84) to use?
>
>Thank you very much, sorry for my English and for my be beginner :-|
>
>Bye.
>
>[ A MIME image / jpeg part was included here. ]

This circuit is from the PIC COOKBOOK Vol2, by Nigel Gardner & Peter
Birnie, page 25. The idea behind it is "In this case the use of the low
cost '54 part introduces a problem since this processor can only be
woken from sleep by an external signel on the reset pin'.

The design is atually a simple burglar alarm, the 'microphone' is a
simple piezo disc sounder, this is glued to the inside of a window pane,
and if the window is struck (or smashed) provides a high enough signal
to wake the PIC.

--

Nigel.

       /--------------------------------------------------------------\
       | Nigel Goodwin   | Internet : spamBeGonenigelgspamBeGonespamlpilsley.demon.co.uk     |
       | Lower Pilsley   | Web Page : http://www.lpilsley.demon.co.uk |
       | Chesterfield    |                                            |
       | England         |                                            |
       \--------------------------------------------------------------/

1998\08\26@103023 by Peter L. Peres

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> phone microphone... correct

No. A phone mike is either electret or carbon. Both need polarization to
work right and I doubt either has enough signal to wake a PIC without some
amplification. On the other hand, the ringer, which *is* piezo nowadays
*will* wake up the PIC if connected to one of its inputs, shunted with 15
Megohms, and whacked with something.

Peter

1998\08\26@154153 by Paul BRITTON

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>and a 100 nf cap... thats .01 uf??
>someone correct me if thats wrong

That's wrong!!

.01uF = 10nF


'Little PIC project problem....HELP'
1998\09\01@224223 by Dale Stemen
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I think you need to add an op amp to your circuit to beef up to mic sign.

Alessandro Marzini wrote:

{Quote hidden}

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