W
W. eWatson
Guest
Subject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
might be done simply?
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J
JW
Guest
On Mon, 14 Feb 2011 08:06:00 -0800 "W. eWatson" <wolftracks@invalid.com>
wrote in Message id: <ijbjta$ijd$1@news.eternal-september.org>:
could attach to a phone handset for recording phone conversations. Radio
Shack used to sell 'em.
wrote in Message id: <ijbjta$ijd$1@news.eternal-september.org>:
Not a stethoscope, but I remember little suction cup microphones that youSubject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
could attach to a phone handset for recording phone conversations. Radio
Shack used to sell 'em.
M
Marc Guardiani
Guest
On Monday, February 14, 2011 11:44:05 AM UTC-5, JW wrote:
-- Marc
Those RatShack suction cup "microphones" did not pick up sound but instead picked up the magnetic field of the speaker in the handset.On Mon, 14 Feb 2011 08:06:00 -0800 "W. eWatson" <wolft...@invalid.com
wrote in Message id: <ijbjta$ijd$1...@news.eternal-september.org>:
Subject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
Not a stethoscope, but I remember little suction cup microphones that you
could attach to a phone handset for recording phone conversations. Radio
Shack used to sell 'em.
-- Marc
A
asdf
Guest
On Mon, 14 Feb 2011 11:44:05 -0500, JW wrote:
certainly won't work to record any sound.
Although they're called microphones, these are just fixed coils intended
to pick up the light magnetic field generated by the line transformer
contained in old landline phones.
For the OP purpose I'd try a contact piezo mic followed by a good low
pass filter and a very high sensitivity and low noise preamp.
Also, a normal electret miniature mic could be stuck to the rubber pipe
of an old stethoscope.
It won't work for anything but old telephones (not cellphones) andNot a stethoscope, but I remember little suction cup microphones that
you could attach to a phone handset for recording phone conversations.
Radio Shack used to sell 'em.
certainly won't work to record any sound.
Although they're called microphones, these are just fixed coils intended
to pick up the light magnetic field generated by the line transformer
contained in old landline phones.
For the OP purpose I'd try a contact piezo mic followed by a good low
pass filter and a very high sensitivity and low noise preamp.
Also, a normal electret miniature mic could be stuck to the rubber pipe
of an old stethoscope.
S
Sjouke Burry
Guest
W. eWatson wrote:
Subject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
With a microphone.
W
whit3rd
Guest
On Feb 14, 8:06 am, "W. eWatson" <wolftra...@invalid.com> wrote:
noise and hand-holding artifacts), and just replace the Y-junction
that goes to the earpieces with a dynamic microphone. You'll
want to have a low-impedance preamplifier for best noise
performance. Maybe negative impedance.
Small speakers make good dynamic microphones.
Electret microphones are already preamplified, but it's uncertain
how 'ideal' they are at the low frequencies in a heartbeat.
Use a stethoscope end as a probe (it's intended to exclude roomSubject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
noise and hand-holding artifacts), and just replace the Y-junction
that goes to the earpieces with a dynamic microphone. You'll
want to have a low-impedance preamplifier for best noise
performance. Maybe negative impedance.
Small speakers make good dynamic microphones.
Electret microphones are already preamplified, but it's uncertain
how 'ideal' they are at the low frequencies in a heartbeat.
W
W. eWatson
Guest
On 2/14/2011 12:38 PM, whit3rd wrote:
However, the quality at the start (beating heart) of the lub-dub may not
indicate the true beat for a few seconds, and the true diastolic
(relaxed) pressure might be a few seconds off. That is, one wants to get
past the noise until the "signals" (systolic and diastolic) are at a
representative point. If not done properly, one can get pretty
incorrect values.
On Feb 14, 8:06 am, "W. eWatson"<wolftra...@invalid.com> wrote:
Subject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
Use a stethoscope end as a probe (it's intended to exclude room
noise and hand-holding artifacts), and just replace the Y-junction
that goes to the earpieces with a dynamic microphone. You'll
want to have a low-impedance preamplifier for best noise
performance. Maybe negative impedance.
Small speakers make good dynamic microphones.
Electret microphones are already preamplified, but it's uncertain
how 'ideal' they are at the low frequencies in a heartbeat.
A heart beat is fine. In fact, it's what I'm looking for.
However, the quality at the start (beating heart) of the lub-dub may not
indicate the true beat for a few seconds, and the true diastolic
(relaxed) pressure might be a few seconds off. That is, one wants to get
past the noise until the "signals" (systolic and diastolic) are at a
representative point. If not done properly, one can get pretty
incorrect values.
G
George Jetson
Guest
"W. eWatson" <wolftracks@invalid.com> wrote in message
news:ijcs0l$ab5$1@news.eternal-september.org...
Did this a couple of weeks ago using a small external computer mic "three
wire plug" and a small plastic cup (about a pint) to help couple the sound.
Put the mike in the container and hold the container with the opening to
your bare chest and the mike trapped inside, the mike just floats. Be very
still.
--
They can have my command prompt when they pry it from my cold dead fingers.
news:ijcs0l$ab5$1@news.eternal-september.org...
On 2/14/2011 12:38 PM, whit3rd wrote:
On Feb 14, 8:06 am, "W. eWatson"<wolftra...@invalid.com> wrote:
Subject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
Use a stethoscope end as a probe (it's intended to exclude room
noise and hand-holding artifacts), and just replace the Y-junction
that goes to the earpieces with a dynamic microphone. You'll
want to have a low-impedance preamplifier for best noise
performance. Maybe negative impedance.
Small speakers make good dynamic microphones.
Electret microphones are already preamplified, but it's uncertain
how 'ideal' they are at the low frequencies in a heartbeat.
A heart beat is fine. In fact, it's what I'm looking for.
However, the quality at the start (beating heart) of the lub-dub may not
indicate the true beat for a few seconds, and the true diastolic (relaxed)
pressure might be a few seconds off. That is, one wants to get past the
noise until the "signals" (systolic and diastolic) are at a representative
point. If not done properly, one can get pretty incorrect values.
Did this a couple of weeks ago using a small external computer mic "three
wire plug" and a small plastic cup (about a pint) to help couple the sound.
Put the mike in the container and hold the container with the opening to
your bare chest and the mike trapped inside, the mike just floats. Be very
still.
--
They can have my command prompt when they pry it from my cold dead fingers.
J
JW
Guest
On Mon, 14 Feb 2011 19:01:58 GMT asdf <asdf@nospam.com> wrote in Message
id: <G_e6p.2248$0b.1245@twister2.libero.it>:
Thanks.
id: <G_e6p.2248$0b.1245@twister2.libero.it>:
Oh. Didn't know that. Learn something new every day...On Mon, 14 Feb 2011 11:44:05 -0500, JW wrote:
Not a stethoscope, but I remember little suction cup microphones that
you could attach to a phone handset for recording phone conversations.
Radio Shack used to sell 'em.
It won't work for anything but old telephones (not cellphones) and
certainly won't work to record any sound.
Although they're called microphones, these are just fixed coils intended
to pick up the light magnetic field generated by the line transformer
contained in old landline phones.
Thanks.
W
W. eWatson
Guest
On 2/14/2011 10:55 PM, George Jetson wrote:
"W. eWatson" <wolftracks@invalid.com> wrote in message
news:ijcs0l$ab5$1@news.eternal-september.org...
On 2/14/2011 12:38 PM, whit3rd wrote:
On Feb 14, 8:06 am, "W. eWatson"<wolftra...@invalid.com> wrote:
Subject is the topic. Anyone ever try it, or have suggestions how it
might be done simply?
Use a stethoscope end as a probe (it's intended to exclude room
noise and hand-holding artifacts), and just replace the Y-junction
that goes to the earpieces with a dynamic microphone. You'll
want to have a low-impedance preamplifier for best noise
performance. Maybe negative impedance.
Small speakers make good dynamic microphones.
Electret microphones are already preamplified, but it's uncertain
how 'ideal' they are at the low frequencies in a heartbeat.
A heart beat is fine. In fact, it's what I'm looking for.
However, the quality at the start (beating heart) of the lub-dub may
not indicate the true beat for a few seconds, and the true diastolic
(relaxed) pressure might be a few seconds off. That is, one wants to
get past the noise until the "signals" (systolic and diastolic) are at
a representative point. If not done properly, one can get pretty
incorrect values.
Did this a couple of weeks ago using a small external computer mic
"three wire plug" and a small plastic cup (about a pint) to help couple
the sound. Put the mike in the container and hold the container with the
opening to your bare chest and the mike trapped inside, the mike just
floats. Be very still.
So you didn't use a stethoscope?