#define PINPIR 2
#define PINBUZZER 7
#define PINRELAY 11

int alarma = 0;

void setup() {

  pinMode(PINPIR, INPUT);
  pinMode(PINBUZZER, OUTPUT);
  pinMode(PINRELAY, OUTPUT);

}


void loop() {

  alarma = 0;

  digitalWrite(PINRELAY, LOW);
  noTone(PINBUZZER);

  while (digitalRead(PINPIR) == 1) {

    if (alarma == 0) {
      tone(PINBUZZER, 495, 1000);
      alarma = 1;
    }

    digitalWrite(PINRELAY, HIGH);
    delay(1000);

  }
}