Digital wristwatch using a HP bubble LED display and an Adafruit Feather M0. Includes a 3D-printed case that fits most watch bands.

Operation

(Sorry, my phone doesn't handle glowy things very well.)

The watch sleeps until you push the button. It then cycles through the time, day, and date, then shuts off again. The battery lasts about 3-4 days between recharges. The time is set over the USB serial connection. Send the time as a UTC Unix timestamp, such as with the command `date +%s`.

The frimware is set for US Eastern Standard Time, and automatically adjusts to Daylight Savings for that timezone. To change the timezone, find this block:

//offset from UTC in hours, change as appropriate for your local timezone. #define NORM_OFF -5 #define DST_OFF -4

Replace the number next to NORM_OFF with the UTC offset for your timezone, and the one next DST_OFF with the offset plus one. For timezones that don't observe DST, or use different rules, more changes may be necessary.