tone()

Description

Generates a square wave of the specified frequency (and 50% duty cycle) on a pin. A duration can be specified, otherwise the wave continues until a call to noTone(). The pin can be connected to a piezo buzzer or other speaker to play tones.

Only one tone can be generated at a time. If a tone is already playing on a different pin, the call to

tone()

Use of the

tone()

It is not possible to generate tones lower than 31Hz. For technical details, see Brett Hagman’s notes.

Syntax

Use the following function variants to generate a tone on a specific pin undefinitely or during a given time:

• tone(pin, frequency)

• tone(pin, frequency, duration)

Parameters

The function admits the following parameters:

• pin

  : the Arduino pin on which to generate the tone.

• frequency

  : the frequency of the tone in hertz. Allowed data types:

  unsigned int

  .

• duration

  : the duration of the tone in milliseconds (optional). Allowed data types:

  unsigned long

  .

Returns

The function returns nothing.

Example Code

Generate a square wave on pin D0 for a second repetitively.

1#define BUZZER_PIN D0 // Example pin
2
3void setup() {
4  pinMode(BUZZER_PIN, OUTPUT);
5}
6
7void loop() {
8  tone(BUZZER_PIN, 1000, 1000); // 1 kHz tone
9  delay(1000);
10}

Notes and Warnings

• If you want to play different pitches on multiple pins, you need to call

  noTone()

  on one pin before calling

  tone()

  on the next pin.
• This function is non-blocking, which means that even if you provide the

  duration

  parameter the sketch execution will continue immediately even if the tone hasn’t finished playing.

See also

• analogWrite()
• Tone Melody
• Pitch Follower
• Tone Keyboard
• Tone Multiple
• PWM