Okay boys 
,
I (hope) ultimated the improvement about the original hackatronics's clock!
After the addiction of the DS3231 RTC to improve the time's accuracy, I improved the program, so now it cans automaticaly spare from RTC to clockISR in case of RTC's fault, and viceversa. Every malfunction will be displayed and sounded.
Please tell me if you agree my works!
Best regards,
KMZ
24_hr_dot_blink_Alarm_RTC_auto_spare_clockISR_set_up_down_beep_.ino (14.3 KB)