"Tim Wescott" wrote in message
...
On Sat, 08 Apr 2017 09:59:56 -0700, edhuntress2 wrote:

On Saturday, April 8, 2017 at 11:45:46 AM UTC-4, Tim Wescott wrote:
On Fri, 07 Apr 2017 08:51:21 -0700, edhuntress2 wrote:

Yo Jim -- and anyone else who may be interested.

I spend an hour last night tracking down some noises in my
furnace
blower, using my usual piece of aquarium hose stuck in my ear
g,
and I wondered if there might be a market for an advanced kind
of
mechanic's stethoscope -- something that ought to be a piece of
cake
for someone like you.

Maybe something like this is on the market. If so, forget it. If
not,
consider this:

I had two noises, from different sources, and the interference
between them made it all but impossible to find the origins of
the
noises. One was some mechanical interference between the
centrifugal
fan and its housing, at one end of the armature shaft; the other
was
vibration resulting from stickiness in the centrifugal throw-out
switch (a fail-safe switch that prevents the gas valve from
opening),
at the other end of the shaft. I finally took the whole thing
apart
and found both problems, but it wasn't easy to find them when
the
motor wasn't running.

So, I wondered about the idea of making a small, cheap,
battery-powered amplifier, with a mike and a headphone jack,
that
contained a couple of active, adjustable audio filters, one
high-pass
and another low-pass. Made a notching filter or bandpass filter
to
make it slick.

I don't play with engines much these days, but I can recall
times
when such a device would have made quick work of tracking down
engine
noises.

There it is. If you make it and sell it, the idea is yours.
Watch out
for patents.

I'm crappy at product marketing, sales, and financing, but good at
"techie" stuff like making this gizmo for cheap in an attractive
housing.

So if you want to do the half that's hard for me, give me a call
and
I'll do the easy part.

Should be able to do the signal processing digitally, so the hard
part
will be making a user interface that allows the pro users to get
the
most out of it while making it easy enough for the ordinary guy so
it
doesn't just get thrown through the wall.

--
Tim Wescott Control systems, embedded software and circuit design
I'm
looking for work! See my website if you're interested
http://www.wescottdesign.com

That's a tempting thought, but look at it from a marketing
perspective:
This is a low-tech, analog device, and as Jim and Clare showed,
there
are slick, digital solutions on the market that even turn a cell
phone
into an audio spectrum analyzer.

I happen to like these simpler solutions, but I don't think a lot
of
people would go for it. The market would be really small. So I
don't
think it's viable except as a hobby thing that one might do for his
own
use and satisfaction.

I think we should pass on this one.

Ooh -- maybe the answer is a smartphone app and a companion
microphone --
and let people who want to scratch up their own microphone go ahead
and
do so.

Hmm. Hmm and hmm. I wonder if it's already done?

--
Tim Wescott

http://www.cablechick.com.au/blog/un...d-audio-jacks/