Playing melodies with tone() in Arduino - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the tone() function do in Arduino?

It plays a sound of a specific frequency on a speaker connected to a pin, creating a tone or note.

beginner

How do you stop a tone that is playing on a pin?

Use the noTone(pin) function to stop the sound on that pin.

beginner

What are the three parameters of tone()?

1. The pin number where the speaker is connected.
2. The frequency of the tone in Hertz.
3. (Optional) The duration in milliseconds to play the tone.

intermediate

Why do we use arrays when playing melodies with tone()?

Arrays store sequences of notes and their durations so the program can play melodies by looping through them.

intermediate

What happens if you call tone() on a pin that is already playing a tone?

The new tone replaces the old one immediately on that pin.

Which function stops a tone playing on a pin?

A tone(pin, 0)

B stopTone(pin)

C noTone(pin)

D endTone(pin)

The correct function to stop a tone is noTone(pin).

What does the second parameter of tone(pin, frequency) represent?

A Frequency in Hertz

B Duration in milliseconds

C Pin number

D Volume level

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

How can you play a melody using tone()?

A By using <code>noTone()</code> repeatedly

B By calling <code>tone()</code> once with all notes

C By connecting multiple speakers to different pins

D By using arrays to store notes and durations and looping through them

Melodies are played by looping through arrays of notes and durations, calling tone() for each.

What happens if you omit the duration parameter in tone()?

A The tone plays forever until <code>noTone()</code> is called

B The tone plays for 1 second

C The tone does not play

D The tone plays for 100 milliseconds

If duration is omitted, the tone plays continuously until stopped.

Which Arduino pin type is required to use tone()?

A Analog input pins

B Digital output pins

C Power pins

D Ground pins

tone() works on digital output pins connected to a speaker or buzzer.

Explain how you would use the tone() function to play a simple melody on an Arduino.

Think about storing notes and durations, then playing each note one by one.

Describe the role of the frequency and duration parameters in the tone() function.

Frequency is like the musical note, duration is how long you hear it.

Practice

1. What does the tone() function do in Arduino?

easy

A. It reads the value from a sensor.

B. It controls the brightness of an LED.

C. It plays a sound at a specific frequency on a speaker.

D. It sends data over the serial port.

Solution

1. Step 1: Understand the purpose of tone()

   The tone() function generates a square wave of the specified frequency on a pin, producing sound through a speaker.

2. Step 2: Compare options with function behavior

   Only It plays a sound at a specific frequency on a speaker. describes playing sound at a frequency, which matches tone() usage.

3. Final Answer:

   It plays a sound at a specific frequency on a speaker. -> Option C

4. Quick Check:

   tone() = plays sound [OK]

Hint: Remember: tone() controls sound frequency, not LEDs or sensors [OK]

Common Mistakes:

• Confusing tone() with analogWrite() for LEDs
• Thinking tone() reads sensor data
• Assuming tone() sends serial data

2. Which of the following is the correct syntax to play a 440 Hz tone on pin 8 for 500 milliseconds?

easy

A. tone(8, 440); delay(500);

B. tone(440, 8, 500);

C. tone(8, 500, 440);

D. tone(8, 440, 500);

Solution

1. Step 1: Recall tone() function parameters

   The correct order is tone(pin, frequency, duration). So pin 8, frequency 440 Hz, duration 500 ms.

2. Step 2: Check each option's parameter order

   tone(8, 440, 500); matches the correct order. tone(8, 440); delay(500); plays tone without duration, relying on delay, which is valid but not the asked syntax.

3. Final Answer:

   tone(8, 440, 500); -> Option D

4. Quick Check:

   tone(pin, freq, duration) = tone(8, 440, 500) [OK]

Hint: Remember tone(pin, frequency, duration) order [OK]

Common Mistakes:

• Swapping frequency and pin parameters
• Confusing duration with frequency
• Omitting duration but expecting timed tone

3. What will the following Arduino code do?

void setup() {
  tone(9, 262, 250);
  delay(300);
  tone(9, 294, 250);
  delay(300);
  noTone(9);
}
void loop() {}

medium

A. Play two notes (C4 and D4) on pin 9 with pauses, then stop sound.

B. Play one continuous note at 262 Hz for 800 ms.

C. Play no sound because noTone() stops all tones immediately.

D. Cause a compile error due to missing loop content.

Solution

1. Step 1: Analyze tone() and delay() calls

   The code plays 262 Hz tone for 250 ms, waits 300 ms, then plays 294 Hz tone for 250 ms, waits 300 ms.

2. Step 2: Understand noTone() effect

   noTone(9) stops any tone on pin 9 after the notes play. The loop is empty, so no repetition.

3. Final Answer:

   Play two notes (C4 and D4) on pin 9 with pauses, then stop sound. -> Option A

4. Quick Check:

   tone + delay + noTone = two notes then stop [OK]

Hint: Check tone frequency and delays to predict sound timing [OK]

Common Mistakes:

• Assuming tones play simultaneously
• Thinking noTone() stops before notes play
• Believing empty loop causes error

4. Which statement correctly describes the behavior of this code snippet:

void setup() {
  tone(7, 330);
  delay(500);
  tone(7, 349);
  delay(500);
  noTone(7);
}
void loop() {}

medium

A. The delay() calls are too short to hear the notes.

B. The second tone replaces the first (which continues until replaced), resulting in sequential notes without overlap.

C. noTone() is called too early, stopping the melody immediately.

D. tone() requires a duration parameter to work correctly.

Solution

1. Step 1: Understand tone() without duration

   Calling tone(pin, freq) plays the tone continuously until stopped or replaced by another tone() on the same pin.

2. Step 2: Analyze timing of tones and delays

   The first tone starts and plays for 500 ms during delay(). The second tone replaces it immediately, playing the new frequency for the next 500 ms. No overlap occurs.

3. Final Answer:

   The second tone replaces the first (which continues until replaced), resulting in sequential notes without overlap. -> Option B

4. Quick Check:

   tone without duration replaced by next tone() = sequential notes [OK]

Hint: tone() without duration continues until next tone() or noTone() [OK]

Common Mistakes:

• Assuming tone() stops automatically after delay
• Thinking tone() calls on same pin cause overlap
• Believing delay controls tone length without duration

5. You want to play a melody of 3 notes (262 Hz, 294 Hz, 330 Hz) each lasting 300 ms on pin 10 with 100 ms pause between notes. Which code snippet correctly achieves this?

hard

A. for (int i = 0; i < 3; i++) {
int notes[] = {262, 294, 330};
tone(10, notes[i], 300);
delay(400);
}
noTone(10);

B. int notes[] = {262, 294, 330};
for (int i = 0; i < 3; i++) {
tone(10, notes[i]);
delay(250);
noTone(10);
delay(100);
}

C. int notes[] = {262, 294, 330};
for (int i = 0; i < 3; i++) {
tone(10, notes[i], 300);
delay(250);
noTone(10);
delay(100);
}

D. int notes[] = {262, 294, 330};
for (int i = 0; i < 3; i++) {
tone(10, notes[i]);
delay(400);
}
noTone(10);

Solution

1. Step 1: Understand timing requirements

   Each note plays 300 ms, plus 100 ms pause, total 400 ms delay between notes.

2. Step 2: Check code for correct tone duration and delay

   for (int i = 0; i < 3; i++) { int notes[] = {262, 294, 330}; tone(10, notes[i], 300); delay(400); } noTone(10); uses tone with duration 300 ms and delay 400 ms, matching timing. noTone(10) after loop stops sound.

3. Step 3: Verify other options

   int notes[] = {262, 294, 330}; for (int i = 0; i < 3; i++) { tone(10, notes[i]); delay(250); noTone(10); delay(100); } calls noTone inside loop, cutting notes short. int notes[] = {262, 294, 330}; for (int i = 0; i < 3; i++) { tone(10, notes[i], 300); delay(250); noTone(10); delay(100); } delays only 250 ms, missing pause. int notes[] = {262, 294, 330}; for (int i = 0; i < 3; i++) { tone(10, notes[i]); delay(400); } noTone(10); plays tone without duration, causing overlap.

4. Final Answer:

   for (int i = 0; i < 3; i++) { int notes[] = {262, 294, 330}; tone(10, notes[i], 300); delay(400); } noTone(10); -> Option A

5. Quick Check:

   tone(duration) + delay(total note+pause) = for (int i = 0; i < 3; i++) { int notes[] = {262, 294, 330}; tone(10, notes[i], 300); delay(400); } noTone(10); [OK]

Hint: Use tone(duration) plus delay(total note+pause) for melody timing [OK]

Common Mistakes:

• Calling noTone() inside loop too early
• Using delay shorter than note+pause
• Omitting duration causing overlapping notes