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Building a T1D smartwatch for my son from scratch

andrewchilds.com

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Re: Building a T1D smartwatch for my son from scratch

#81

Post by raminf »

andrewchilds wrote: post #73
raminf wrote: post #71

Awesome work building it all from scratch! Hate to be that guy, but was using something hackable like a PineTime ( https://pine64.org/devices/pinetime/ ) and doing a direct BLE connection to the device using the Blood Glucose Profile ( https://www.bluetooth.com/specifications/specs/glucose-profi... ) not an option? Another approach could be to hack one of those cheap fitness trackers ( https://rbaron.net/blog/2018/05…

I didn't even know about the BLE Glucose Profile - thank you! Valid question about the PineTime! I'd agree that it is an option, although with the dev kit out of stock, flashing a custom firmware would be tricky. I think that's probably what happened, I looked at this page back when I was first starting out on this and was scared off: https://pine64.org/documentation/PineTime/Further_informatio...

I didn't mean to send you down a rabbit-hole since you've already built an awesome-looking platform. Just googling, came across a devkit: https://ameridroid.com/products/pinetime-smart-watch?variant...

The DevKit is mainly there to allow easy access the SWD pins. It can be flashed via a Pi: https://wiki.pine64.org/wiki/PineTime_Devkit_Wiring

Aaron Christophel (go-to guy for hacking wearables) has a video on flashing them via an ESP32: https://www.youtube.com/watch?v=Iu6RoXRZxOk

For OTA flash, some folks have had good luck with https://gadgetbridge.org

For those interested in going the cheap-o activity tracker route, here's another old thread on Hackaday, featuring Aaron. More good info in the comments: https://hackaday.com/2019/02/20/custom-firmware-for-cheap-fi...

Also, one last tidbit: I know the idea was to stay away from the more expensive devices, but many Apple and Android watches have built-in BLE central capability so they can scan and connect to peripherals without having to go through the phone. In later models, they can even scan in the background and update complications.

Again, not remotely as cool as building one's own device!

Re: Building a T1D smartwatch for my son from scratch

#83

Post by mdorazio »

lagrange77 wrote: post #4

Very cool! I love the texture of the enclosure. I guess that's not possible with an FDM printer, right?

Actually it is! Although your tolerances will not be as good as with a fusion jet printer. For FDM, print on a textured bed and play with the “fuzzy skin” settings in Cura. You’ll get quite close to what’s shown in the author’s pictures.

Re: Building a T1D smartwatch for my son from scratch

#84

Post by mdorazio »

Regarding the fact that your son’s watch has 2x the battery life of the others, did you ever test the real capacity of each of the batteries? Speaking from experience, batteries sourced from random Chinese suppliers can have wildly different real-world specs, even within the same lot.

Re: Building a T1D smartwatch for my son from scratch

#85

Post by andrewchilds »

mdorazio wrote: post #84

Regarding the fact that your son’s watch has 2x the battery life of the others, did you ever test the real capacity of each of the batteries? Speaking from experience, batteries sourced from random Chinese suppliers can have wildly different real-world specs, even within the same lot.

Good to know! I was wondering that as well, but wasn't able to easily swap/test different batteries since I was soldering them to the PCB and then sealing the watch. I'll research how to test capacity across different batteries.

I chart the last 7 days of battery voltage in the companion iOS app, and it does look like they're drawing current differently. My son's watch can sit in deep sleep for days and lose very little charge, unlike the other watches which seem to continue to draw current even though the ESP32-S3 is in deep sleep.

Re: Building a T1D smartwatch for my son from scratch

#86

Post by K0balt »

hommelix wrote: post #40
K0balt wrote: post #27

Great project! Idk if this might be useful or not, but there is a smartwatch platform (bangle.js 2) that uses the NRF52840 chip (extremely low power, solid BLE support, works with Espruino, micro python, arduino, and other IDEs) battery life is around a week, depending on what you run, of course. The watch includes an always-on color transflective display, GPS, accelerometer , barometer, haptic motor, compass, sound,…

Another interesting watch is zswatch. It uses a nrf mcu as well. https://github.com/jakkra/ZSWatch https://www.youtube.com/watch?v=MmCzV0jV9hs

This looks awesome!

Re: Building a T1D smartwatch for my son from scratch

#87

Post by nonplus »

This is a really cool project. Your post is the first time I am seeing the figures on how much others also hate CGM notifications.

I have been working on software for the G1 headset to display glucose data without any audible alarms, just a visual notification.

The issues I run into are:

* Dexcom sensors have limited Bluetooth connections (with pump support), so I need to pull data from a phone.

* Battery life (I can get 9 hours maybe with a not always on display, a far cry from 6 days).

* xDrip gets readings slower than directly from dexcom.

* General UI edge cases for missed readings.

Thank you for sharing your work, it's validation that others are experiencing this problem and maybe my visual solution will be useful to others (and a watch/audible/haptic device also might be a good complement to what I have now, my solution is not supposed to be the only way to get CGM data.) https://github.com/ltomes/rel-a/tree/feature/xDrip

Re: Building a T1D smartwatch for my son from scratch

#88

Post by lagrange77 »

mdorazio wrote: post #83
lagrange77 wrote: post #4

Very cool! I love the texture of the enclosure. I guess that's not possible with an FDM printer, right?

Actually it is! Although your tolerances will not be as good as with a fusion jet printer. For FDM, print on a textured bed and play with the “fuzzy skin” settings in Cura. You’ll get quite close to what’s shown in the author’s pictures.

Nice, thanks!
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