I'm also looking at doing a health app of sorts - turns out that quite a lot of people with type 1 diabetes get very sweaty when they're having a hypoglycaemic episode. So I'm looking to create a galvanic skin response reader (with DroidScript android app to do the alerting).
I've got a GSR from Seeedstudio which needs 3.3V to power it - can I do this from one of the digital IOs (which means I can turn it off when not reading to save power?)
Alternatively, am I right in thinking that skin capacitance varies with moisture in the same way that resistance does? IOW can I dispense with the separate GSR altogether and just use capsense?
The other part of this project (unfortunately the end-user I have in mind has deteriorating eyesight) is a simple bit of code (actually running on the Android) which counts the number of consecutive button presses and then performs tasks based on this (so 1 click is open google assistant, 2 clicks is say time, 4 clicks to phone a particular number, 5 clicks is get GPS location and send an email with a link to that location on google maps etc)
Kudos for inventing this extremely cool bit of kit BTW - my first attempts faltered when I realised how awkward it was going to be to put arduino plus bluetooth breakount plus GSR plus battery back in wearable form that was technophobe-friendly!
Has anyone done a 3D design for a star-trek communicator badge yet? :-)