Although ready-made real-time clock (RTC) ... Here is the circuit diagram of a compact RTC module, based on the popular RTC IC DS1307, ... when it comes to Arduino. Here is a really simple tutorial ...

But the arduino start the code by adjusting the time to 2pm again. So once u set already, comment that line out and upload again. Eagle file for schematic & layout (DS1307 RTC Module V1.0) ...

There’s a good chance you’ve seen “Nixie clocks” on the Internet that replace the classic cold cathode tubes with similarly sized LCD panels. The hook is that the LCDs can s… ...

He’s made a real-time-clock module controlled by a rubidium frequency standard, ... and GPS module together with an ATMega32U4 miniature Arduino-compatible board and an LCD display.