Arduino Audio Alarm

beep.ino

int relay = 2;
int input = 3;

int startBeep = 0;
int beepLength = 1000;

void setup() {
  pinMode(relay, OUTPUT);
  pinMode(input, INPUT);
  Serial.begin(9600);
}

void loop() {
  if (startBeep == 0) {
    int reading = digitalRead(input);
    if (reading == 1) {
      Serial.println("Start Beep");
      startBeep = millis();
      digitalWrite(relay, HIGH);
      delay(500);
    }
  } else {
    int now = millis();
    if (startBeep + beepLength < now) {
      Serial.println("End Beep");
      startBeep = 0;
      digitalWrite(relay, LOW);
      delay(500);
    }
  }
}