int led = 13;
int alarmSignal = 12;
bool alarmON = false;
const int turnOffDelay = 1000;
int timeTurnOff;
int crossingSineSignal = 2;
bool crossingSineActive = false;
int crossingSineThreshold = 20;
int ldr = A0;
int ldrVal;
int ldrThreshold = 50;
int btn = 3;
int btnVal;
int pir = 4;
bool pirVal = false;
int intensityDivider = 4;
int intensityCounter = 0;

void setup() {
			// Uso del Monitor Serial para calibración y reporte
  	Serial.begin(9600);
  	pinMode(led, OUTPUT);
  	pinMode(alarmSignal, OUTPUT);
// resistencia interna de carga para fototransistor optoacoplado
  	pinMode(crossingSineSignal, INPUT_PULLUP);
  	pinMode(btn, INPUT_PULLUP);
  		// sensor pull up
  	pinMode(ldr, INPUT_PULLUP);
  	attachInterrupt(digitalPinToInterrupt(crossingSineSignal), crossingSine, RISING);
}
void loop() {
  	btnVal = digitalRead(btn);
  	digitalWrite(led, btnVal);
  	pirVal = digitalRead(pir);
  	ldrVal = analogRead(A0);
  	if(alarmON) {
    		if(millis() > timeTurnOff || ldrVal <= ldrThreshold) {
      			alarmON = false;
    		}
  	} else {
    		digitalWrite(alarmSignal, false);
  	} 
  	if(btnVal && ldrVal > ldrThreshold && pirVal) {
    		timeTurnOff = millis() + turnOffDelay;
    		alarmON = true;
  	}
}
void crossingSine() {
  	Serial.println(millis(),DEC);
  	if(alarmON) {
    		intensityCounter++;
    		if(intensityCounter >= intensityDivider) {
      			intensityCounter = 0;
      			digitalWrite(alarmSignal, true);
    		}else {
      			digitalWrite(alarmSignal, false);
    		}
		}
}