I'm going to buck the trend and say this is an excellent idea, but it should absolutely NOT be used for its indended purpose. If OP wants to track his own insulin levels, fine, but to put DIY, uncertified, learn-as-you-go medical monitoring device on someone else, let alone your own son is f*cking bonkers.
Just to clear up the confusion here: there's basically no risk to this device. It's not inventing numbers on its own. It's simply a secondary display to the same data that's on the phone. The phone alarms are still there, and can't be disabled, not to mention the insulin pump, which also alarms independently.
Calm down. I've been building medical device software for close to two decades and the level of engineering in this device is at least what I see on multi-million dollar projects that are going for FDA approval.
Medical Design process basically exists (oversimplifying of course) because the engineers are not the users. It's entirely possible for one person to build something that far exceeds the quality and performance of an off the shelf device simply because they care to do a good job and have constant feedback on how it works.
There's a lot to be said for scratching your own itch!
Plenty of folks out there can't afford any treatment. This kid has it seems every form of treatment known to man and his dad is trying to make it more convenient for him, with the added benefit that this may make it cheaper/easier for the rest of the world. His level of risk tolerance improves the world and will cause his son no problems, while also avoiding learned helplessness.
For T1Ds, you pretty much constantly have to monitor your blood glucose level. I used to use a Pebble for this, now I use an Apple Watch. The Apple Watch backgrounds the monitoring all the damn time, so I have to click multiple buttons and wait to see my blood sugar, when the number is immediately available on my phone (the watch didn’t used to be this bad). The entire point of this hardware project is eliminating that latency.
