Doorbell

// Doorbell
// Press the button and the buzzer plays a happy "ding-dong".

const int BUTTON_PIN = 2;    // Pushbutton on pin 2 (other side to GND)
const int BUZZER_PIN = 8;  // Active buzzer: S on pin 8

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP); // Released = HIGH, pressed = LOW
  pinMode(BUZZER_PIN, OUTPUT);
}

// Let the buzzer beep for a while
void beep(int howLong) {
  digitalWrite(BUZZER_PIN, HIGH);
  delay(howLong);
  digitalWrite(BUZZER_PIN, LOW);
}

void loop() {
  if (digitalRead(BUTTON_PIN) == LOW) {  // Someone presses the bell!
    beep(300);      // "Ding"
    delay(150);
    beep(600);      // "Dong"
    delay(1000);    // Wait a bit, so the bell does not keep ringing
  }
}