This is an example Arduino sketch that builds an Alarm Clock out of an Arduino Uno, an LCD Keypad Shield (the one with the parallel interface, not the I2C), a DS1307 Real Time Clock, and a buzzer.

The example can basically display date and time, set an alarm, ring a buzzer when the time comes, and snooze.

The code was implemented based on the following FSM design. For details on the operation of the clock/alarm, please read the description in the example code.

The code makes use of the Jeelab RTClib and OSEPP LCDKeypad libraries.