#include <Arduino.h>

const int PIN_PIR = 2; // Infrared movement sensor pin;
const int PIN_RELAIS = 12; // Relais pin;
int pirStatus = 0;

bool isAlarmSystemReady = false;

bool alarmSystemIsReady() {
   bool isReady = false;
   int calibrationTime = 5;

   for(int i = calibrationTime; i > 0; i--) {
      Serial.println(i);
      delay(1000);
   }

   isReady = true;

   return isReady;
}

// SETUP
void setup() {
   Serial.begin(9600);

   pinMode(PIN_RELAIS, OUTPUT);
   pinMode(PIN_PIR, INPUT);

   if(alarmSystemIsReady()) {
      isAlarmSystemReady = true;
      Serial.println("Alarm system is armed.");
   }
}


// LOOP
void loop() {
   if(isAlarmSystemReady) {
      pirStatus = digitalRead(PIN_PIR);

      if(pirStatus == HIGH) {
         Serial.println("There is somebody.");
         digitalWrite(PIN_RELAIS, LOW);

         delay(5000);
         digitalWrite(PIN_RELAIS, HIGH);
         isAlarmSystemReady = false;
         setup();
      }
   }
}