Adjusts by GPS NEO6M data, 6-digit display (hh: mm: ss)
 The DS1307 RTC is adjusted, displayed on 4 digits (hh: mm)
 Correction of the hour every hour, we display 6 digits to see if correction of the seconds.
 At the end of the adjustment time (1 min) returns to the 4-digit display.
 If action bp date, displays the date (6 digits (dd / mm / yy)) for approximately 6 seconds
 If bp reset action during the date display, we switch to 4-digit or 6-digit mode depending on the original state.
 Function off all night: 6 Displays Off from 11 p.m. to 6 a.m.
 Note: if action bp dates when displays Off, the time is displayed for approximately 10 seconds.
POSSIBLE ATtiny Tone Bell 
SEE https://youtu.be/jCmF5OtTugU