Passive buzzers are simple electronic components that can produce sound when driven with an oscillating signal. Unlike active buzzers, which have built-in oscillators, passive buzzers require an external signal to generate sound. In the Arduino environment, passive buzzers can be used to create various tones and melodies, making them ideal for projects that require audio feedback or alerts.

Examples:

1. Basic Tone Generation with a Passive Buzzer

   To generate a basic tone using a passive buzzer with an Arduino, you'll need the following components:

   • Arduino board (e.g., Arduino Uno)
   • Passive buzzer
   • Jumper wires
   • Breadboard (optional)

   Wiring:

   Connect the passive buzzer to the Arduino as follows:

   • Connect one pin of the buzzer to a digital pin on the Arduino (e.g., pin 8).
   • Connect the other pin of the buzzer to the GND pin on the Arduino.

   Code:

   const int buzzerPin = 8; // Pin connected to the buzzer
   
   void setup() {
    pinMode(buzzerPin, OUTPUT); // Set the buzzer pin as an output
   }
   
   void loop() {
    tone(buzzerPin, 1000); // Send a 1 kHz signal to the buzzer
    delay(1000); // Wait for 1 second
    noTone(buzzerPin); // Stop the tone
    delay(1000); // Wait for 1 second
   }

   In this example, the tone() function is used to generate a 1 kHz signal on the buzzer pin, producing a sound. The noTone() function stops the sound. The loop alternates between playing the tone for 1 second and stopping it for 1 second.

2. Playing a Simple Melody

   You can also use a passive buzzer to play simple melodies. Here’s how to play a short tune:

   Code:

   const int buzzerPin = 8;
   
   // Notes of the melody
   int melody[] = {
    262, 294, 330, 349, 392, 440, 494, 523
   };
   
   // Note durations: 4 = quarter note, 8 = eighth note, etc.
   int noteDurations[] = {
    4, 4, 4, 4, 4, 4, 4, 4
   };
   
   void setup() {
    // No setup needed for this example
   }
   
   void loop() {
    for (int thisNote = 0; thisNote < 8; thisNote++) {
      int noteDuration = 1000 / noteDurations[thisNote];
      tone(buzzerPin, melody[thisNote], noteDuration);
   
      // Pause between notes
      int pauseBetweenNotes = noteDuration * 1.30;
      delay(pauseBetweenNotes);
      noTone(buzzerPin);
    }
    delay(1000); // Wait for 1 second before repeating the melody
   }

   This example plays a simple scale using the tone() function to generate different frequencies corresponding to musical notes. The noteDurations array controls the length of each note.