From goveil1 on hackster.io:The chimes, played by the 2nd Arduino and the Adafruit Wave Shield, can be soft set to be Westminster, Chime on the hour only, Chime but be silent at night, Cuckoo clock sounds or completely silent. The two Arduinos communicate via I2C so that the sound can be ‘fire and forget’ and the clock keep running. // Read more: original article.