Portable breath measurement mask (breath by breath O2, CO2)

Beginner here.

I was wondering if it would be possible to build and Arduino based breath measurement mask. These measure breathing volume and O2 concentration (and also CO2) while inhaling and exhaling. This allows estimating the O2 consumed on each breath.

There are several commercial products that do this, and they are usually used for VO2max testing for athletes.

More recently there are some portable masks for sale:

http://www.carefusion.com/our-products/respiratory-care/metabolic-carts/oxycon-mobile-device

http://www.cosmed.it/en/products/cardio-pulmonary-exercise-testing/k5-wearable-metabolic-technology

Can anyone point me to some ideas of how to:

a) measure volume flow. I imagine maybe a fan with a motor in the main air entry/exit of the mask, and measure the current generated on the motor by the airflow (in and out). b) measure O2 concentration on the in and out air.

I figure a few complications with this use: - exhaled air includes humidity - measurement sampling rate has to be high enough to keep up with the breath cycle

regards Lucas

OP here. Uppon searching a bit more I found this student projetc that does exactly what I intented.

Bio-Metric Mask (abr 2014)

http://www.ece.rutgers.edu/files/capstone/capstone2014/Bio-Metric-Mask/Capstone-Poster-2.0.pdf

https://www.youtube.com/watch?v=Fin-rD61B7Y&feature=youtu.be

Still wonder how precise the results were, relative to a comercial mask.

Also if other this this is the way to go.

regards Lucas