This seems pretty cool. I was a big fan of Spire[1] and their device that monitored steps and breathing. Spire seems to have completely left the consumer market and I would love another device that does that stuff.
Thanks for the link. Yep, it seems a few companies have developed technologies and then left the space, or never made it to market. Spirosmart seemed promising - https://ubicomplab.cs.washington.edu/publications/spirosmart... - (and Senosis was subsequently acquired by Google) but I've never seen a real-world clinical application.
1. https://www.spirehealth.com/