Buzzer and TonalBuzzer in Raspberry Pi

Introduction

A buzzer is a small device that makes sound when powered. A TonalBuzzer lets you play different tones or notes, like a simple music player.

To make a beep sound when a button is pressed.

To alert someone with a sound in a project, like a timer or alarm.

To play simple melodies or tones for fun or feedback.

To signal different events with different sounds.

To learn how to control hardware sounds with code.

Syntax

Raspberry Pi

from gpiozero import Buzzer, TonalBuzzer

buzzer = Buzzer(pin_number)
buzzer.on()  # turns buzzer on
buzzer.off() # turns buzzer off

# For TonalBuzzer
from gpiozero import TonalBuzzer

tonal_buzzer = TonalBuzzer(pin_number)
tonal_buzzer.play(frequency)  # plays a tone

# To stop
tonal_buzzer.stop()

Replace pin_number with the GPIO pin connected to the buzzer.

TonalBuzzer can play different frequencies (tones), while Buzzer just turns on/off.

Examples

This turns the buzzer on for 1 second, then off.

Raspberry Pi

from gpiozero import Buzzer
import time

buzzer = Buzzer(17)
buzzer.on()
time.sleep(1)
buzzer.off()

This plays a 440 Hz tone (A4 note) for 2 seconds, then stops.

Raspberry Pi

from gpiozero import TonalBuzzer
import time

buzzer = TonalBuzzer(18)
buzzer.play(440)  # plays A4 note
time.sleep(2)
buzzer.stop()

This plays a simple scale of notes, each for half a second.

Raspberry Pi

from gpiozero import TonalBuzzer
import time

buzzer = TonalBuzzer(18)
notes = [262, 294, 330, 349, 392]  # C4, D4, E4, F4, G4
for note in notes:
    buzzer.play(note)
    time.sleep(0.5)
buzzer.stop()

Sample Program

This program plays five musical notes one after another on the buzzer connected to GPIO pin 18.

Raspberry Pi

from gpiozero import TonalBuzzer
import time

buzzer = TonalBuzzer(18)

# Play a short melody
melody = [440, 494, 523, 587, 659]  # A4, B4, C5, D5, E5
for tone in melody:
    buzzer.play(tone)
    time.sleep(0.4)
buzzer.stop()

Important Notes

Make sure your buzzer supports tones if you use TonalBuzzer.

Use a resistor if needed to protect your Raspberry Pi and buzzer.

GPIO pins must be set correctly to avoid damage.

Summary

Buzzer makes simple on/off sounds.

TonalBuzzer plays different tones by frequency.

Use these to add sound feedback or simple music to your Raspberry Pi projects.

Practice

1.

What is the main difference between a Buzzer and a TonalBuzzer in the gpiozero library?

easy

A. Buzzer makes a simple beep; TonalBuzzer can play different tones by frequency.

B. Buzzer can play music; TonalBuzzer only beeps once.

C. Buzzer requires more power than TonalBuzzer.

D. Buzzer is software only; TonalBuzzer is hardware only.

Solution

1. Step 1: Understand Buzzer functionality

   A Buzzer in gpiozero produces a simple on/off beep sound without tone variation.

2. Step 2: Understand TonalBuzzer functionality

   A TonalBuzzer can play different tones by changing the frequency, allowing melodies or varied sounds.

3. Final Answer:

   Buzzer makes a simple beep; TonalBuzzer can play different tones by frequency. -> Option A

4. Quick Check:

   Buzzer simple beep, TonalBuzzer frequency tones = C [OK]

Hint: Remember: TonalBuzzer = tones, Buzzer = simple beep [OK]

Common Mistakes:

• Thinking Buzzer can play melodies
• Confusing hardware and software roles
• Assuming TonalBuzzer only beeps once

2.

Which of the following is the correct way to import and create a TonalBuzzer on GPIO pin 17 using gpiozero?

from gpiozero import TonalBuzzer
buzzer = ?

easy

A. TonalBuzzer(17)

B. TonalBuzzer(pin=17)

C. TonalBuzzer('GPIO17')

D. TonalBuzzer('pin17')

Solution

1. Step 1: Check gpiozero TonalBuzzer constructor

   The constructor takes the GPIO pin number as an integer, e.g., 17.

2. Step 2: Validate syntax

   Using TonalBuzzer(17) is correct; keyword argument pin=17 is not standard, and strings like 'GPIO17' are invalid.

3. Final Answer:

   TonalBuzzer(17) -> Option A

4. Quick Check:

   Use integer pin number directly = A [OK]

Hint: Use integer GPIO pin number without quotes [OK]

Common Mistakes:

• Passing pin as string instead of integer
• Using keyword argument pin=17 incorrectly
• Adding quotes around pin number

3.

What will be the output behavior of this code snippet on a Raspberry Pi with a buzzer connected to GPIO 18?

from gpiozero import TonalBuzzer
from time import sleep
buzzer = TonalBuzzer(18)
buzzer.play(440)
sleep(1)
buzzer.stop()

medium

A. The buzzer plays a random tone for 1 second.

B. The buzzer beeps once immediately and stops.

C. The code raises an error because play() is not a method.

D. The buzzer plays a 440 Hz tone for 1 second, then stops.

Solution

1. Step 1: Understand TonalBuzzer play() method

   The play(frequency) method plays a tone at the given frequency in Hz, here 440 Hz (A note).

2. Step 2: Analyze code timing

   The tone plays for 1 second due to sleep(1), then buzzer.stop() stops the sound.

3. Final Answer:

   The buzzer plays a 440 Hz tone for 1 second, then stops. -> Option D

4. Quick Check:

   play(440) + sleep(1) + stop() = D [OK]

Hint: play(frequency) sounds tone; sleep controls duration [OK]

Common Mistakes:

• Thinking play() is not a valid method
• Assuming beep instead of tone
• Ignoring sleep duration effect

4.

Identify the error in this code that tries to make a buzzer beep for 2 seconds:

from gpiozero import Buzzer
from time import sleep
buzzer = Buzzer(22)
buzzer.play()
sleep(2)
buzzer.stop()

medium

A. sleep(2) should be sleep(2000) for milliseconds.

B. Buzzer has no play() method; use on() instead.

C. GPIO pin 22 is invalid for buzzer use.

D. buzzer.stop() should be buzzer.off().

Solution

1. Step 1: Check Buzzer class methods

   The Buzzer class uses on() and off() to control buzzing, not play().

2. Step 2: Validate other code parts

   sleep(2) correctly waits 2 seconds; GPIO 22 is valid; stop() is not a method for Buzzer.

3. Final Answer:

   Buzzer has no play() method; use on() instead. -> Option B

4. Quick Check:

   Buzzer uses on()/off(), not play() = B [OK]

Hint: Buzzer uses on()/off(), TonalBuzzer uses play() [OK]

Common Mistakes:

• Using play() with Buzzer instead of on()
• Confusing sleep units (seconds vs milliseconds)
• Calling stop() on Buzzer which lacks that method

5.

You want to play a simple melody using TonalBuzzer on GPIO 13. Which code snippet correctly plays two tones (440 Hz and 880 Hz) each for 0.5 seconds in sequence?

from gpiozero import TonalBuzzer
from time import sleep
buzzer = TonalBuzzer(13)

# Which code plays the melody correctly?

A) buzzer.play(440)
sleep(0.5)
buzzer.play(880)
sleep(0.5)
buzzer.stop()

B) buzzer.play(440)
sleep(0.5)
buzzer.stop()
buzzer.play(880)
sleep(0.5)
buzzer.stop()

C) buzzer.play(440)
buzzer.play(880)
sleep(1)
buzzer.stop()

D) buzzer.on()
sleep(0.5)
buzzer.off()
buzzer.on()
sleep(0.5)
buzzer.off()

hard

A. Play 440 Hz and 880 Hz simultaneously, sleep, then stop.

B. Play 440 Hz, sleep, stop, then play 880 Hz, sleep, stop again.

C. Play 440 Hz, sleep, then play 880 Hz, sleep, then stop buzzer.

D. Turn buzzer on and off twice without tone control.

Solution

1. Step 1: Understand sequential tone playing

   To play tones in sequence, call play(frequency) for each; subsequent calls change the frequency seamlessly without needing stop() between.

2. Step 2: Analyze each option

   Play 440 Hz, sleep 0.5s, play 880 Hz (switches seamlessly), sleep 0.5s, stop correctly sequences tones without gaps. Play 440 Hz, sleep 0.5s, stop, play 880 Hz, sleep 0.5s, stop introduces silence between tones. Play 440 Hz immediately followed by 880 Hz, sleep 1s, stop effectively plays mostly 880 Hz. Turn buzzer on and off twice without tone control produces simple beeps, no specific frequencies.

3. Final Answer:

   Play 440 Hz, sleep, then play 880 Hz, sleep, then stop buzzer. -> Option C

4. Quick Check:

   play() changes frequency seamlessly = A [OK]

Hint: play(new_freq) switches tones seamlessly; no stop needed between [OK]

Common Mistakes:

• Stopping buzzer unnecessarily between tones
• Trying to play multiple tones at once
• Using on()/off() instead of play() for tones