Lesson Four: Sound Alarm
This program makes your alarm clock seem even more familiar with a loud beep at alarm time. To make the speaker work, you need a way to create and stop tones without interrupting the counting of the clock, so you'll use more variable and millis() to constantly check the time and control the speaker.
Triggering a beep when it is alarmTime is similar to creating a message on the screen: It's an action that takes place when a condition is met. In this program, you saw how you had to modify the way that action works because it has two parts: on and off.