Piezo Speaker Siren

/*
Connect the positive side of the buzzer to pin 3 on the Arduino using a breadboard,
then connect the negative side of the piezo to a 1k resistor. Finally, connect the other side
of the 1k resistor to one of the ground (GND) pins on the Arduino.
*/

#define buzzerPin 3
#define minFreq 30
#define maxFreq 10000

void setup() {
}

void loop() {
  // siren goes up
  for (int i = minFreq; i <= maxFreq; i++) {
    tone(buzzerPin, i);
    delay(1);
  }

  // siren goes down
  for (int i = maxFreq; i >= minFreq; i--) {
    tone(buzzerPin, i);
    delay(1);
  }

  noTone(buzzerPin);
}