N
Neon John
Hey guys,
I'm looking for some interesting ideas that are both practical AND
cheap to monitor respiration air flow.
I've developed a collapsed lung and my pulmonologist has put me on a
CPAP machine to try and reinflate it. Problem is, after 6 weeks of
trying, I can't stand the thing. I want to do some self-research and
see what I can learn, particularly if the CPAP is having any effect.
So I want to build a quickie anemometer. Actually, 2. One to look at
my nose flow and another to look at my mouth flow. It's important to
capture the flow waveform, as (at least on the spirometer) one can see
where the bad lung quits working and the good one finishes the
exhalation.
During my sleep study, they attached a rig that held a tiny tube in
front of each nostril and one in front of my mouth. The tubes lead to
a box containing pressure transducers, conditioners and something to
stick the signal on an Ethernet cable. Of course I don't want to do
something that complicated. Ideally this would be something that I
could knock out in a day using materials on-hand.
What I'm thinking about is Arduino-based, something that would
digitize each waveform and spit it over the USB bus to a capture
program. Then I can analyze the data in OO or GnuPlot or whatever.
Very minimal software effort desired.
First thought was a low range MEMS pressure transducer but looking on
Digikey and Mouser, they're kinda expensive and require signal
conditioning and amplification, at least on the ones they keep in
stock.
Second thought is a self-heated thermistor bead. Major problem is the
signal would have to be linearized which would take a little more
software effort than I want to dedicate to this project.
Third idea is a self-heated LM35. With a 50 ma load on the output an
LM35 in the TO-92 package self-heats about 10 deg C. I can shoot the
signal right into an Arduino's analog input with no conditioning.
Question that remain include whether the low air flow of sleep
breathing will cool the thing enough to matter and what its time
constant is. Another problem is that a TO-92 package is kinda large
to have dangling from one's nose and upper lip.
So I thought I'd toss this problem out to you guys and see what
innovative ideas you come up with.
Thanks,
John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address
I'm looking for some interesting ideas that are both practical AND
cheap to monitor respiration air flow.
I've developed a collapsed lung and my pulmonologist has put me on a
CPAP machine to try and reinflate it. Problem is, after 6 weeks of
trying, I can't stand the thing. I want to do some self-research and
see what I can learn, particularly if the CPAP is having any effect.
So I want to build a quickie anemometer. Actually, 2. One to look at
my nose flow and another to look at my mouth flow. It's important to
capture the flow waveform, as (at least on the spirometer) one can see
where the bad lung quits working and the good one finishes the
exhalation.
During my sleep study, they attached a rig that held a tiny tube in
front of each nostril and one in front of my mouth. The tubes lead to
a box containing pressure transducers, conditioners and something to
stick the signal on an Ethernet cable. Of course I don't want to do
something that complicated. Ideally this would be something that I
could knock out in a day using materials on-hand.
What I'm thinking about is Arduino-based, something that would
digitize each waveform and spit it over the USB bus to a capture
program. Then I can analyze the data in OO or GnuPlot or whatever.
Very minimal software effort desired.
First thought was a low range MEMS pressure transducer but looking on
Digikey and Mouser, they're kinda expensive and require signal
conditioning and amplification, at least on the ones they keep in
stock.
Second thought is a self-heated thermistor bead. Major problem is the
signal would have to be linearized which would take a little more
software effort than I want to dedicate to this project.
Third idea is a self-heated LM35. With a 50 ma load on the output an
LM35 in the TO-92 package self-heats about 10 deg C. I can shoot the
signal right into an Arduino's analog input with no conditioning.
Question that remain include whether the low air flow of sleep
breathing will cool the thing enough to matter and what its time
constant is. Another problem is that a TO-92 package is kinda large
to have dangling from one's nose and upper lip.
So I thought I'd toss this problem out to you guys and see what
innovative ideas you come up with.
Thanks,
John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address