OK, this is only tangentially related but it has been on my mind lately and I need to rant:
I am T1 diabetic. Over the last decade, a LOT has happened to improve my life, especially in regards to no longer needing to check glucose levels with blood, as glucose sensors you wear on your arm have become ubiquitous.
It started with a dedicated device that you needed to hold up to the sensor to get a reading (much nicer than pricking your finger) to that sensor being able to notify the dedicated device of high/low glucose values (yay! Sleep through the night, knowing you'll be woken up if something is wrong) to the sensor now constantly streaming glucose values to your phone.
Which is fantastic.
In theory.
In practice, there are two companies making these sensors (OK, there's a couple more, but they suck way more and are much less commonly used).
And both of their closed-source apps suuuuuuuuck. They do the bare minimum and nothing more. (Actually, it's worse than that. Ask me if you want to know. It's its own rant.)
Then there's xdrip+, a FANTASTIC app made by diabetics for diabetics. Instead of just showing you "this is your glucose" and sounding an alarm, once, when it's required, you can (just off the top of my head): Set an arbitrary amount of alarms with their own behaviors, which can be configured to vary by time of day; show the glucose everywhere (notification, lock screen, home screen,...); mute alarms for a custom time; do not sound an alarm if you're trending in the correct direction fast enough; do not sound the alarm multiple times if your are jittering around the threshold; notify other people automatically in case of emergency; and roughly 1000 things more. The app is well maintained, and of course open source.
Can you guess what the problem is?
That's right, manufacturers disapprove of using this app. For the worse one of the two sensors mentioned, the community reverse engineered the communication and it is now working perfectly with the app. For the better sensor, they can't and won't due to fear of legal repercussions.
It's my health. And I need to decide between worse hardware and useless software.
There's no technical reason for this. I dream of the EU passing a law that requires manufacturers of wearable medical devices to publish the comm protocols and to legitimize use of third party software.
Rant over.