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[on:]

Is there anyone out there in the medical field that can recommend a sensor for measuring the hydrogen level in one's breath?  It doesn't have to be super accurate (preferably semi-inexpensive) but should be able to measure large changes in breath hydrogen levels.  I have some medical experiments I'm looking to conduct on myself  and thought this would be a perfect project with an Arduino.

[Reply #1 on:]

What types of levels are you expecting?  I would guess low ppm as I have tested my breath with a TCD and did not see any hydrogen to my 100ppm DL.  Vapours from the other end can have hydrogen in the 40% range!, thus the "blue angel".

[Reply #2 on:]

From what I can tell it looks like normal breath hydrogen levels are in the neighborhood of 5 ppm.  Looks like I would need a sensor capable of detecting those levels up to about 70ppm.

[Reply #3 on:]

At this level it is going to be tough. I believe most sensors are only good to 25ppm or so. If you need accurate number, I would suggest a gas chromatograph with a DID detector. In addition, hydrogen can diffuse like crazy, so be careful in your sampling system.