How to Use a Buzzer (or Piezo Speaker)

Operation

A piezoelectric buzzer is typically composed of a piezoelectric diaphragm, a cavity with an orifice and connections for the electrical terminals.

It requires an alternate voltage to operate, from a few volts to a few tens of volts ( 3V to 30V)

Code

int speakerPin = 9;
int length = 15; 
char notes[] = "ccggaagffeeddc"; 
int beats[] = { 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 4 };
int tempo = 300;
void playTone(int tone, int duration)
{
 for (long i = 0; i < duration * 1000L; i += tone * 2)
 {
   digitalWrite(speakerPin, HIGH);
   delayMicroseconds(tone);
   digitalWrite(speakerPin, LOW);
   delayMicroseconds(tone);
 }
}
void playNote(char note, int duration)
{
 char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C' };
 int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956 };
 for (int i = 0; i < 8; i++) {
   if (names[i] == note) {
     playTone(tones[i], duration);
   }
 }
}
void setup()
{
 pinMode(speakerPin, OUTPUT);
}
void loop()
{
 for (int i = 0; i < length; i++)
 {
   if (notes[i] == ' ')
   {
     delay(beats[i] * tempo); 
   }
   else
   {
     playNote(notes[i], beats[i] * tempo);
   }
   delay(tempo / 2); 
 }
}

Connections

Buzzer + ---> D9

Buzzer - ---> GND