>
> Getting the sensitivity/frequency cut-offs will require some work,
> but then, I don't get any money for the idea....;)
>

Well, now that's not necessarily entirely out of the
question...depending on the quantities thereof required ;-)

Actually, your thinking is pretty much in line with my own, recalling
the old stethoscope engine noise analyzers, with the long tube, of my
old high school days in the 60's ;-(

Modifying a telescoping antenna, mounting the electret in the handle,
would make a nifty shirt pocket sniffer.  Not sure about the
changing effects on acoustical resonance or whether it cares a hoot,
though.

 What do you suggest...cost and solutions wise.  I could
really use a mentor anyway, to help break the way into PICs...my
background is mostly RF comm in the good ol' pre-IC days.  The
transistor had been invented by then, but we all knew that was just
another one of those fads, soon to pass away...

Regards/Roger, in Bangkok