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Buzzer

A passive piezoelectric buzzer that generates audio tones when driven by a rapidly oscillating digital signal.

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Piezo Buzzer

Unlike an active buzzer (which beeps at a fixed frequency when given 5V), this is a passive buzzer. It requires a rapidly oscillating signal (like a PWM wave) to produce sound. Changing the frequency of the signal changes the pitch of the sound.

ActuatorsAudio OutputPiezoelectric

Overview

The OpenHW Simulator plays the sound through your computer's speakers using the Web Audio API. Use the standard Arduino tone() function for easy frequency control.

Musical Note Frequencies

Here are some common frequencies you can use with the tone() function:

Note	Frequency
C4 (Middle C)	262 Hz
D4	294 Hz
E4	330 Hz
F4	349 Hz
G4	392 Hz
A4	440 Hz

Pin Reference

Pin	Type	Description
GND (-)	power	Negative terminal — connect to GND.
SIG (+)	digital	Positive terminal — connect to a digital/PWM pin.

Configurable Attributes

Attribute	Type	Default	Description
volume	number	50	Master volume for this buzzer in the simulator (0-100).
frequency	number	440	Default resonant frequency configuration (internal).

Working Principle

A piezoelectric disc physically deforms when voltage is applied across it. By rapidly applying and removing voltage (e.g., 440 times per second), the disc vibrates and creates a sound wave (440 Hz pitch, or the note A4).

Wiring Diagram

Connect the buzzer's negative pin to GND and the positive pin to a digital output pin on the Arduino (e.g., Pin 3).

Example Arduino Code

const int buzzerPin = 3;

// Frequencies for C4, D4, E4, F4, G4, A4, B4, C5
int notes[] = {262, 294, 330, 349, 392, 440, 494, 523};
int durations[] = {200, 200, 200, 200, 200, 200, 200, 400};

void setup() {
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  for (int i = 0; i < 8; i++) {
    tone(buzzerPin, notes[i], durations[i]);
    delay(durations[i] + 30); // Add a slight pause between notes
  }
  
  noTone(buzzerPin);
  delay(1000);
}

Simulation Notes

• Ensure your browser tab is not muted. Modern browsers block audio playback until the user clicks on the page, so you must interact with the simulator before audio will play.
• Hardware Conflict: The tone() function uses Timer 2 on the ATmega328P (Arduino Uno). This conflicts with PWM output on pins 3 and 11. You cannot use analogWrite() on pins 3 or 11 while a tone is playing.

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