For a good clock must use a RTC (real-time clock) like DS1307. For Arduino enthusiasts and hobbylist exists some RTC module with DS1307, but you can made yourself a good RTC module like me. Original schematic is from DS1307 datasheet, but I redesigned schematic using freeversion of Eagle PCB Software: Note: Battery is CR2032, like in schematic... in boards is a little error A full schematic for RTC clock with Arduino is: Compared to other schematics that can adjust time (reset clock at 0:00...
