Arduino 220 detector with debounce + interrupts

sketch.uno

#define AC_PIN 3
#define RF_PIN 2
#define LED_PIN 13

volatile int counter = 0;
volatile int ac_status = 0;
volatile unsigned long ac_timer;

int ON[] = {2, 2, 2, 2, 1, 4, 4, 4, 4, 5, 1, 4, 4, 4, 4, 4, 4, 5, 2, 2, 1, 4, 4, 4, 6}; //The RF code that will turn the ON
int OFF[] = {2, 2, 2, 2, 1, 4, 4, 4, 4, 5, 1, 4, 4, 4, 4, 4, 4, 5, 2, 2, 2, 2, 2, 2, 3}; //The RF code that will turn the OFF

void acCheck()
{
  ac_timer = millis();
  if (ac_status == 0) {
    // AC ON state
    ac_status = 1;
  }
}

void setup() {
  // put your setup code here, to run once:

  Serial.begin(9600);

  pinMode(AC_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(AC_PIN), acCheck, CHANGE);
  pinMode(LED_PIN, OUTPUT);

  //set timer1 interrupt at 1Hz
  TCCR1A = 0;// set entire TCCR1A register to 0
  TCCR1B = 0;// same for TCCR1B
  TCNT1  = 0;//initialize counter value to 0
  // set compare match register for 1hz increments
  OCR1A = 15624;// = (16*10^6) / (1*1024) - 1 (must be <65536)
  // turn on CTC mode
  TCCR1B |= (1 << WGM12);
  // Set CS12 and CS10 bits for 1024 prescaler
  TCCR1B |= (1 << CS12) | (1 << CS10);
  // enable timer compare interrupt
  TIMSK1 |= (1 << OCIE1A);
}

ISR(TIMER1_COMPA_vect) { //timer1 interrupt 1Hz toggles status

  unsigned long timer = millis();
  if (ac_status > 0) {
    if (timer > ac_timer + 500) {
      // AC OFF
      ac_status = 0;
      ac_timer = 0;
      acOFF();
    } else if (ac_status == 1) {
      acON();
      ac_status = 2;
    } else if (ac_status == 2) {
      if (counter++ > 3) {
        digitalWrite(LED_PIN, HIGH);
        counter = 0;
      } else {
        digitalWrite(LED_PIN, LOW);
      }
    }
  } else if (++counter > 1) {
    digitalWrite(LED_PIN, HIGH);
    counter = 0;
  } else {
    digitalWrite(LED_PIN, LOW);
  }

}

void loop() {

}

void acON() {

  Serial.println("On");
  sendCode(ON);
}

void acOFF() {

  Serial.println("Off");
  sendCode(OFF);
}

void sendCode(int code[]) {
  int timeDelay = 5;

  // The LED will be turned on to create a visual signal transmission indicator.
  digitalWrite(LED_PIN, HIGH);

  //initialise the variables
  int highLength = 0;
  int lowLength = 0;

  //The signal is transmitted 6 times in succession - this may vary with your remote.
  for (int j = 0; j < 6; j++) {
    for (int i = 0; i < (sizeof(code) / sizeof(int)); i++) {
      switch (code[i]) {
        case 1: // SH + SL
          highLength = 3;
          lowLength = 3;
          break;
        case 2: // SH + LL
          highLength = 3;
          lowLength = 7;
          break;
        case 3: // SH + VLL
          highLength = 3;
          lowLength = 92;
          break;
        case 4: // LH + SL
          highLength = 7;
          lowLength = 3;
          break;
        case 5: // LH + LL
          highLength = 7;
          lowLength = 7;
          break;
        case 6: // LH + VLL
          highLength = 7;
          lowLength = 92;
          break;
      }

      /* Transmit a HIGH signal - the duration of transmission will be determined
         by the highLength and timeDelay variables */
      digitalWrite(RF_PIN, HIGH);
      delayMicroseconds(highLength * timeDelay);

      /* Transmit a LOW signal - the duration of transmission will be determined
         by the lowLength and timeDelay variables */
      digitalWrite(RF_PIN, LOW);
      delayMicroseconds(lowLength * timeDelay);
    }
  }
  //Turn the LED off after the code has been transmitted.
  digitalWrite(LED_PIN, LOW);
}