The_Official_Raspberry_Pi_-_Beginner’s_Book_Vol1,_2018 (1)

140 THE OFFICIAL RASPBERRY PI BEGINNER'S GUIDE

Controlling a buzzer in Python

Controlling an active buzzer through the GPIO Zero library is almost identical to controlling an

LED, in that it has on and off states. You need a different, function, though: buzzer. Start a

new project in Thonny and save it as Buzzer, then type the following:

from gpiozero import Buzzer

from time import sleep

As with LEDs, GPIO Zero needs to know which pin your buzzer is connected to in order to

control it. Type the following:

buzzer = Buzzer( 15 )

From here, your program is almost identical to the one you wrote to control the LED; the only

difference (apart from a different GPIO pin number) is you’re using buzzer in place of led.

Type the following:

while True:

buzzer.on()

sleep( 1 )

buzzer.off()

sleep( 1 )

Click the Run button and your buzzer will begin to buzz: one second on, and one second off.

If you are using a passive buzzer rather than an active buzzer, you’ll only hear a brief click every

second instead of a continuous buzz: this is because a passive buzzer lacks an oscillator to

create the rapidly changing signal which makes the plates inside the buzzer vibrate.

Click the Stop button to exit the program, but make sure the buzzer isn’t making a sound

at the time otherwise it will continue to buzz until you run your program again!

CHALLENGE: A BETTER BUZZ

How could you change the program to make the buzzer

sound for a shorter time? Can you build a circuit so the

buzzer is controlled by a button?