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 ...

[Barzok] has a very minimal clock build. It takes a handful of LED arrays with an integrated driver, an Arduino Nano, a real-time clock module, and a voltage regulator.

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.

It is designed for the use of any power source including a discharging battery as primary supply. The RX8900CE module uses digital processing temperature compensated crystal oscillator (DTCXO) ...

For playing the music, it uses the BY8001 MP3 Player module and for the alarm clock it uses the DS3231 Real Time Clock module.