Developers, makers and hobbyists looking for a real time clock module complete with an Arduino library, may be interested in the Kraztech Real Time Clock Module created by developer Christopher ...

He’s made a real-time-clock module controlled by a rubidium frequency standard, and since it also includes a GPS clock he can track local time dilation effects by comparing the two.

Using an Arduino Mega, DS3231 Real Time Clock Module, Eight stepper motors 28BYJ-48 with ULN2003 Driver, 82 cm Wooden strip 19x19mm, Steel Wire 1m, 46 Washer head screw 4.2 x 14 mm, 16 Button head ...

The build relies on that old stalwart, the Arduino Uno, to run the show. It’s hooked up to a DS3231 real-time clock module so it can keep accurate time for long periods, as is befitting a clock.