Building a (T1D) smartwatch from scratch

If you have type 1 diabetes, you need to keep track of and manage your blood glucose levels closely, as if these levels dip too low, it can quickly spiral into a medical emergency. Andrew Childs’ 9 year old son has type 1 diabetes, and Childs was unhappy with any of the current offerings on the market for children to keep track of their blood glucose levels. Most people suggested an Apple Watch, but he found the Apple Watch “too much device” for a kid, something I personally agree with.

It ships with so many shiny features and apps and notifications. It’s beautifully crafted. It’s also way too distracting for a kid while they’re at school. Secondly, it doesn’t provide a good, reliable view of his CGM data. The Dexcom integration is often backgrounded, doesn’t show the chart, only the number and an arrow. People use hacks like creating calendar events just to see up-to-date data. And the iOS settings, Screen Time, and notification systems have ballooned into a giant ball of complexity. What we need is something simple.
↫ Andrew Childs

And so Childs set out to design and prototype a smartwatch just for his son to wear, trying to address the shortcomings of other offerings on the market along the way, and possibly even bring it to market for other people in similar situations. After six months, he managed to create several prototypes, with both the software and hardware designed from the ground up, that he and his son still wear to this day, to great satisfaction. Since Childs didn’t really know where to go from there and how to turn what he had into an actual product people could be, he decided to document his effort online.

In the process, he had to overcome a ton of hurdles, from iOS’ strict BLE limitations, difficult-to-reach soldering points that can’t be moved due to the small size of the PCB, optimising the battery life, dealing with glass manufacturing, and many other issues, big and small. Oh and also, he was a software engineer, not a hardware one, so he had to learn a lot of new skills, from working with 3D modeling to PCB design. In the end, though, he’s now got a few devices that look quite professionally made, that are incredibly easy to repair, and that are focused solely on those things he and his son need.

This project has increased the quality of life for his son, and that’s genuinely all that really matters here.