tone() function for frequency generation in Arduino - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output sound frequency?

Consider this Arduino code snippet using the tone() function. What frequency will the buzzer produce?

Arduino

void setup() {
  tone(8, 1000);
}

void loop() {
  // no code here
}

A No sound (tone not started)

B 500 Hz tone on pin 8

C 1000 Hz tone on pin 8

D Tone on pin 8 but frequency unknown

💡 Hint

The second parameter of tone() is the frequency in Hertz.

The tone() function starts a square wave of the given frequency on the specified pin. Here, 1000 means 1000 Hz.

❓ Predict Output

intermediate

What happens when duration is specified?

What will happen when this Arduino code runs?

Arduino

void setup() {
  tone(9, 440, 500);
}

void loop() {
  // no code here
}

A Pin 9 outputs a continuous 440 Hz tone

B Pin 9 outputs a 500 Hz tone for 440 milliseconds

C No tone is produced because duration is too short

D Pin 9 outputs a 440 Hz tone for 500 milliseconds, then stops

💡 Hint

The third parameter of tone() is the duration in milliseconds.

The tone() function with three parameters plays the tone for the specified duration then stops automatically.

🔧 Debug

advanced

Why does this code produce no sound?

This Arduino code is supposed to play a 1000 Hz tone on pin 7, but no sound is heard. What is the problem?

Arduino

void setup() {
  tone(7);
}

void loop() {
  // no code here
}

A Missing frequency parameter in tone() call

B tone() requires a duration parameter

C tone() cannot be called in setup()

D Pin 7 is not a PWM pin

💡 Hint

Check the parameters required by tone().

The tone() function requires at least two parameters: pin and frequency. Calling it with only the pin does nothing.

🧠 Conceptual

advanced

What happens if tone() is called twice on the same pin?

If you call tone(6, 500); and then immediately call tone(6, 1000);, what will happen?

A Both tones play simultaneously on pin 6

B The tone changes to 1000 Hz immediately on pin 6

C The first tone continues and the second call is ignored

D The Arduino will crash due to conflict

💡 Hint

Calling tone() on the same pin replaces the previous tone.

The second tone() call stops the first tone and starts the new frequency on the same pin.

❓ Predict Output

expert

How many tones are playing after this code runs?

Given this Arduino code, how many pins are producing sound simultaneously?

Arduino

void setup() {
  tone(3, 400);
  tone(5, 600);
  tone(3, 800);
  noTone(5);
}

void loop() {
  // no code here
}

A One tone on pin 3 at 800 Hz

B Two tones: pin 3 at 400 Hz and pin 5 at 600 Hz

C One tone on pin 5 at 600 Hz

D No tones playing

💡 Hint

Remember that calling tone() on the same pin replaces the previous tone, and noTone() stops the tone on that pin.

The first tone(3, 400); starts 400 Hz on pin 3. Then tone(5, 600); starts 600 Hz on pin 5. Next, tone(3, 800); replaces the 400 Hz tone on pin 3 with 800 Hz. Finally, noTone(5); stops the tone on pin 5. So only pin 3 plays an 800 Hz tone.