The Official Raspberry Pi Beginner's Guide by Gareth Halfacree

Author:Gareth Halfacree
Language: eng
Format: epub
Publisher: Raspberry Pi Press

Figure 6-10: Connecting a buzzer to the GPIO pins

Controlling a buzzer in Scratch

Recreate the program you used to make the LED flash — or load it, if you saved it earlier. Use the drop-down in the green blocks to select number 15 , so Scratch is controlling the correct GPIO pin.

View code (Example 41) → Click the green flag, and your buzzer will begin to buzz: one second on, one second off. If you only hear the buzzer clicking once a second, your buzzer is passive, not active. While an active buzzer generates a rapidly changing signal, known as an oscillation , to make the metal plates vibrate, a passive buzzer needs to receive an external oscillation signal rather than producing one itself. When you turn it on using Scratch, the plates only move once and stop, making the ‘click’ sound until the next time your program switches the pin on or off.

Click the red octagon to stop your buzzer, but do so when it’s not making a sound, otherwise the buzzer will buzz until you run your program again!

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