It could be using nonlinear optical shenanigans for CO2 measurement. I met someone at NASA using optical mixing and essentially using a beat frequency to measure atmospheric CO2 with all solid state COTS components (based on absorption of solar radiation). Technique was called optical heterodyne detection.
I’ve also seen some mid IR leds being sold, although none near the 10um CO2 wavelength.
COTS CO2 monitors exist for ~$100 and could probably be modified to messure breathing gases. They’ll likely be extremely slow.
The cheapest way to measure CO2 concentration, although likely most inaccurate and slow, would be with the carbonic acid equilibrium reaction in water and a pH meter.
Ultimately the reason it’s not popular is probably because it doesn’t seem that useful. Breathing is automatic and regulated by blood CO2 concentration; I find it hard to believe that the majority of the population, with otherwise normal respiratory function, would be so off the mark. Is there strong evidence to suggest this is the case?
Does “COTS” stand for “commercial off-the-shelf” or is this some more technical acronym related to CO2 measurements?
Ultimately the reason it’s not popular is probably because it doesn’t seem that useful. Breathing is automatic and regulated by blood CO2 concentration; I find it hard to believe that the majority of the population, with otherwise normal respiratory function, would be so off the mark. Is there strong evidence to suggest this is the case?
I agree that this wouldn’t be useful for the majority of the population. (Somebreathinggurus claim that poor breathing is responsible for pretty much every health problem ever including anxiety, depression, sleep problems, heart problems, brain fog, gastrointestinal problems, headaches, chronic pain, etc. I don’t buy these strong claims.) As I tried to make clear in the original question, my own interest in this is personal: I’ve been having chronic shortness of breath for over a decade and the doctors just shrug and say “maybe it’s anxiety” and give me inhalers which don’t work. But I suspect others like me are not all that rare. This video (that explains air hunger in terms of carbon dioxide levels and overbreathing) has 53k views and 2.2k likes; Reddit is full of people complaining about air hunger; something like 8% of all EMS responses in the US are from a combination of “respiratory distress” and “shortness of breath” (most of which I assume are not life-threatening; see this Quora question for some evidence, and my one and only time so far on an ambulance to the ER was due to feeling like I couldn’t breathe which in retrospect was probably due to overbreathing). So again, I don’t think the majority of the population would need to do anything about their breathing, but that seems like quite a high bar that basically no health problem could clear. I’m instead suggesting that it’s quite a common problem (but I don’t know exactly how common), and asking why this device which seems like it would be helpful for this common problem is virtually unknown.
The $100 CO2 monitors do not measure CO2, they measure VOCs, which in typical home and office settings closely correlates with CO2 (because humans emit both at a relatively constant rate and humans are the main sources of both in typical home and office settings).
Does this mean that a cheap “pseudo-capnometer” can be created which measures VOCs collected via a nasal cannula? Or would measuring VOCs instead of CO2 change the results at that level (but why?)?
There exist inexpensive real co2 sensors, e.g. https://www.sparkfun.com/products/22396 . Datasheet says only updates every 5 seconds & 60s response time “for achieving 63% of a respective step function”, which I guess is what parent comment means by “They’ll likely be extremely slow”.
Probably worth searching e.g. digikey for sensors with faster response time.
It could be using nonlinear optical shenanigans for CO2 measurement. I met someone at NASA using optical mixing and essentially using a beat frequency to measure atmospheric CO2 with all solid state COTS components (based on absorption of solar radiation). Technique was called optical heterodyne detection.
I’ve also seen some mid IR leds being sold, although none near the 10um CO2 wavelength.
COTS CO2 monitors exist for ~$100 and could probably be modified to messure breathing gases. They’ll likely be extremely slow.
The cheapest way to measure CO2 concentration, although likely most inaccurate and slow, would be with the carbonic acid equilibrium reaction in water and a pH meter.
Ultimately the reason it’s not popular is probably because it doesn’t seem that useful. Breathing is automatic and regulated by blood CO2 concentration; I find it hard to believe that the majority of the population, with otherwise normal respiratory function, would be so off the mark. Is there strong evidence to suggest this is the case?
Thank you!
Does “COTS” stand for “commercial off-the-shelf” or is this some more technical acronym related to CO2 measurements?
I agree that this wouldn’t be useful for the majority of the population. (Some breathing gurus claim that poor breathing is responsible for pretty much every health problem ever including anxiety, depression, sleep problems, heart problems, brain fog, gastrointestinal problems, headaches, chronic pain, etc. I don’t buy these strong claims.) As I tried to make clear in the original question, my own interest in this is personal: I’ve been having chronic shortness of breath for over a decade and the doctors just shrug and say “maybe it’s anxiety” and give me inhalers which don’t work. But I suspect others like me are not all that rare. This video (that explains air hunger in terms of carbon dioxide levels and overbreathing) has 53k views and 2.2k likes; Reddit is full of people complaining about air hunger; something like 8% of all EMS responses in the US are from a combination of “respiratory distress” and “shortness of breath” (most of which I assume are not life-threatening; see this Quora question for some evidence, and my one and only time so far on an ambulance to the ER was due to feeling like I couldn’t breathe which in retrospect was probably due to overbreathing). So again, I don’t think the majority of the population would need to do anything about their breathing, but that seems like quite a high bar that basically no health problem could clear. I’m instead suggesting that it’s quite a common problem (but I don’t know exactly how common), and asking why this device which seems like it would be helpful for this common problem is virtually unknown.
The $100 CO2 monitors do not measure CO2, they measure VOCs, which in typical home and office settings closely correlates with CO2 (because humans emit both at a relatively constant rate and humans are the main sources of both in typical home and office settings).
Does this mean that a cheap “pseudo-capnometer” can be created which measures VOCs collected via a nasal cannula? Or would measuring VOCs instead of CO2 change the results at that level (but why?)?
>Does this mean that a cheap “pseudo-capnometer” can be created which . . . ?
I doubt it, but don’t know for sure because I don’t know anything about the mechanisms by which people outgas the VOCs.
There exist inexpensive real co2 sensors, e.g. https://www.sparkfun.com/products/22396 . Datasheet says only updates every 5 seconds & 60s response time “for achieving 63% of a respective step function”, which I guess is what parent comment means by “They’ll likely be extremely slow”.
Probably worth searching e.g. digikey for sensors with faster response time.