You can get a Casio F-91W and replace the movement with a Sensor Watch board. The watch then becomes a water resistant temperature compensated quartz wristwatch. It's a literally world class time piece. I calibrated mine and now it deviates a few seconds per year. It's insane how good this thing is. Low power, battery lasts over a year.
It's a fully programmable ARM microcontroller. You can write "watch faces" for it. There's a 2nd factor codes face that lets you log in like you're James Bond on the Nintendo 64. One of the coolest projects I've ever worked on. I made it possible to calibrate the pulsometer, a feature I use frequently at work.
It's a fully programmable ARM microcontroller. You can write "watch faces" for it. There's a 2nd factor codes face that lets you log in like you're James Bond on the Nintendo 64. One of the coolest projects I've ever worked on. I made it possible to calibrate the pulsometer, a feature I use frequently at work.
https://www.sensorwatch.net/
They even developed a custom LCD that's even more awesome than the original.