Comment by ricardobeat 18 hours ago
It’s hard to achieve a good screen/case ratio in DIY projects. The screen components are bulky and it’s difficult to fit everything in small enclosures without producing custom boards, mass produced hardware has a ton of advantages there.
Sensor Watch. Open source replacement movement PCB for the Casio F‑91W and other similar watches. Open source firmware. ARM Cortex M0+ microcontroller that you can develop for using standard GNU toolchains. Battery lasts years. Temperature sensor makes it a temperature compensated quartz watch. They're even making custom LCDs now.
Wear mine every day. Contributed some improvements to the pulsometer and TOTP faces. Was even maintainer for a while. Really nice community. If you want something awesome to hack on, this is it.
I believe that's the concept behind the PineTime.
It would be cool if someone made a mass produced "watch" that's all the hardware but none of the firmware. So a tiny computer on your wrist that doesn't do anything out of the box, and you can make it do whatever you want. Maybe a watch, maybe something else. It just provides the housing, microcontroller, battery, screen, etc., and an SDK.