BLE Dual Mode finally coming up

Started poking around at my many year old (and mostly useless) BLE Nano's.  Turns out they're supposed to be able to support S130.  After a few hours, gave up, and finally threw them out so I won't waste more time on them next year.

A little more googling, turns out Adafruit has a feather that does S130 (actually S132 in this case).
So...

Add this doo dad:

And I have a phone free CGMS, again.

So, with the Mi Band I can get custom notifications to it from Xcode, you can also send a notification that will make it buzz until you acknowledge, very cool.  Just have to convert all the Xcode for pairing etc. to Arduino land.  More on that later, much later.

Onto the hardware.  The feather can serve as Central to the Mi Band (ie. masquerade as a phone) and as peripheral to the iPhone.  It can be a casual relationship with the iPhone, where the phone is just a front end for calibrations, everything else lives on the feather, no phone, no problem.