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Traditional mechanical alarm clocks have a bell on top that rings, but digital alarm clocks can make other noises. Simple battery-powered alarm clocks make a loud buzzing sound, or other similar noise to wake a sleeper, while novelty alarm clocks can speak, laugh, or sing. Some alarm clocks have radios that start playing at specified times, and are known as clock radios. A progressive alarm clock, still new in the market, can have different alarms for different times (see Next-Generation Alarms). The first mechanical alarm clock was invented by Levi Hutchins, of New Hampshire, in the United States, in 1787. This device he made only for himself however, and it only rang at 4 AM, in order to wake him for his job.[1] The French inventor Antoine Redier was the first to patent an adjustable mechanical alarm clock, in 1847.