noTone() to stop sound in Arduino - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output on the buzzer?

Consider this Arduino code snippet. What will the buzzer do when this runs?

Arduino

tone(8, 1000); // Play 1000 Hz tone on pin 8
noTone(8); // Stop the tone immediately

A The buzzer never plays any sound.

B The buzzer plays a 1000 Hz tone briefly then stops immediately.

C The buzzer plays a 500 Hz tone instead of 1000 Hz.

D The buzzer plays a continuous 1000 Hz tone without stopping.

💡 Hint

noTone() stops any tone playing on the specified pin.

The tone() function starts playing a tone on pin 8 at 1000 Hz. The noTone() function immediately stops any tone on pin 8, so the buzzer only plays briefly.

🧠 Conceptual

intermediate

Why use noTone() in Arduino?

Which of these best explains why you would use noTone() in an Arduino sketch?

A To change the volume of the buzzer sound.

B To start playing a tone on a pin at a specific frequency.

C To stop a tone playing on a pin so the buzzer becomes silent.

D To make the buzzer beep faster.

💡 Hint

Think about what happens when you want silence after a sound.

noTone() stops the tone on the pin, making the buzzer silent. It does not start or change tones or volume.

🔧 Debug

advanced

Why does the buzzer keep playing?

This code is supposed to play a tone and then stop it after 2 seconds, but the buzzer keeps playing. What is the problem?

Arduino

tone(9, 440);
delay(2000);
noTone(9);

A tone(9, 0) does not stop the tone; noTone(9) should be used instead.

B delay(2000) is too short to stop the tone.

C tone() needs a third parameter to stop the tone.

D The buzzer is connected to the wrong pin.

💡 Hint

Check how to properly stop a tone playing on a pin.

Calling tone(pin, 0) does not stop the tone. The correct way to stop a tone is to call noTone(pin).

📝 Syntax

advanced

Identify the syntax error

Which option contains the correct syntax to stop a tone on pin 7?

A noTone(7);

B noTone 7;

C noTone(7)

D noTone7();

💡 Hint

Remember how functions are called in Arduino (C++).

The correct syntax is noTone(7); with parentheses and a semicolon. Options B, C, and D are missing parentheses or semicolon or have wrong syntax.

🚀 Application

expert

How many times does the buzzer beep?

What is the number of beeps heard from the buzzer after running this code?

Arduino

for (int i = 0; i < 3; i++) {
  tone(10, 1000);
  delay(200);
  noTone(10);
  delay(200);
}

A 6 beeps

B No beeps

C 1 beep

D 3 beeps

💡 Hint

Each loop iteration plays one beep then stops it.

The loop runs 3 times. Each time it plays a tone for 200 ms, then stops it and waits 200 ms. So, 3 beeps total.