When was the first alarm clock invented?
In 427 B.C., the Greek philosopher Plato made the first water alarm clock. Levi Hutchins in the year 1787 invented he first mechanical alarm clock at Concord in New Hampshire in the United States. This alarm clock only rang at 4 in the morning.
In 1847, Antoine Redier invented the first modern alarm clock that allows people to set time. In the 1940s, James F. Reynolds invented the radio alarm clock.