...everything looks like a nail.

I put some thought into what controller I should use for the watch, and what it should display. 

My initial idea was to use an AtTiny chip. Then, I though that an AVR might give me a bit more flexibility, Arduino bootloader, etc. Well, then why not an ARM? SAMD21 will do nicely. Finally I thought - I'll just use an nRF52832 - ARM Cortex M4, gives me BLE to fool around with, and that's the platform I am most familiar with anyway.

Also, after thinking about LEDs, bubble displays and tiny 7-segment displays, I decided on an OLED since that gives the possibility for some fun graphics.