Buzzer and TonalBuzzer in Raspberry Pi - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Buzzer on GPIO pin 17.

Raspberry Pi

from gpiozero import Buzzer
buzzer = Buzzer([1])

Drag options to blanks, or click blank then click option'

A17

B18

C27

D22

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong GPIO pin number.

Passing the pin number as a string instead of an integer.

The Buzzer is connected to GPIO pin 17, so we pass 17 to the Buzzer constructor.

2fill in blank

medium

Complete the code to turn the buzzer on.

Raspberry Pi

from gpiozero import Buzzer
buzzer = Buzzer(17)
buzzer.[1]()

Drag options to blanks, or click blank then click option'

Aoff

Bon

Ctoggle

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using off() instead of on().

Using toggle() which switches state but does not guarantee on.

To turn the buzzer on, call the on() method.

3fill in blank

hard

Fix the error in the code to play a tone of 440 Hz for 1 second using TonalBuzzer.

Raspberry Pi

from gpiozero import TonalBuzzer, Tone
import time
buzzer = TonalBuzzer(17)
buzzer.play([1])
time.sleep(1)
buzzer.stop()

Drag options to blanks, or click blank then click option'

ATone(frequency=440)

BTone(440)

C440

D440Hz

Attempts:

3 left

💡 Hint

Common Mistakes

Passing an integer directly instead of a Tone object.

Using a string like '440Hz' which is invalid.

The play() method requires a Tone object with frequency=440 to play the tone correctly.

4fill in blank

hard

Fill both blanks to create a TonalBuzzer on pin 18 and play a 523 Hz tone.

Raspberry Pi

from gpiozero import TonalBuzzer, Tone
buzzer = TonalBuzzer([1])
tone = Tone([2])
buzzer.play(tone)

Drag options to blanks, or click blank then click option'

A18

B17

C523

D440

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up pin numbers and frequencies.

Passing frequency to TonalBuzzer instead of Tone.

The TonalBuzzer is created on pin 18 and the Tone is set to 523 Hz (C note).

5fill in blank

hard

Fill all three blanks to create a dictionary of tones with their frequencies and play the 659 Hz tone.

Raspberry Pi

from gpiozero import TonalBuzzer, Tone
buzzer = TonalBuzzer([1])
tones = {'E': Tone([2]), 'G': Tone(784)}
buzzer.play(tones[[3]])

Drag options to blanks, or click blank then click option'

A17

B659

C'E'

D'G'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong pin number.

Using the wrong frequency for the 'E' tone.

Not using quotes around the dictionary key.

The buzzer is on pin 17, the 'E' tone frequency is 659 Hz, and we play the tone labeled 'E'.

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