If you find one that lets you extract the data directly, please post. The one I got just has this proprietary app that communicates with it via bluetooth, and I'd much rather have it in a proper time-series format and automate the data-pull.
Also, if you do end up getting a CPAP, those things have a fascinating amount of time-series data stored on their SD cards. If I recall mine logs about 20 independent datapoints, which is a surprising number for something that's just blowing air into your nose. :D But for example, it can detect when you're snoring and it logs a boolean for that all night long.
The off-the-shelf devices look pretty appealing for not having to build the actual on-finger package from scratch. I'd bet the Bluetooth device would be easy to read from something other than an app so I'll give that a try.
Neat. I think this device is fundamentally different from mine in that it appears to stream the events over bluetooth rather than storing them locally and then downloading the "session" over bluetooth. Make sure you don't get one like mine if you want to stream them.