Alarm Clock original pen and ink and watercolour illustration by Rosie Brooks

An alarm clock is a device designed to wake a person up at a specific time. Typically, an alarm clock includes a clock face or digital display with numbers indicating the current time, as well as a set of controls that allow the user to set the alarm time and choose various settings such as the sound of the alarm or whether it should repeat daily.

When the alarm time is reached, the alarm clock will emit a loud sound or vibration to awaken the sleeper. Common sounds include beeping, ringing, and music. Some alarm clocks also include features such as gradually increasing the volume of the alarm to wake the sleeper more gently, or playing nature sounds or other calming noises to help the sleeper fall asleep.

Alarm clocks have been used for many decades and are a common household item around the world. While many people now use smartphones or other digital devices as alarm clocks, traditional standalone alarm clocks remain popular due to their simplicity, reliability, and ease of use.