Interrupt2

#include <IRremote.h>
#define triacPulse A0
#define ZCD 2           // Zero Cross Detector
#define RECV_PIN 7      // IR Pin

IRrecv irrecv(RECV_PIN);
decode_results results;
unsigned long key_value = 0;
const byte ZCDinterruptPin = 2;
int x=0;
bool speed1 = false;
bool speed2 = false;
bool speed3 = false;

void setup() {
  Serial.begin(9600);
  irrecv.enableIRIn();
  irrecv.blink13(true);
  pinMode(ZCD, INPUT_PULLUP);
  pinMode(triacPulse, OUTPUT);
  //  attachInterrupt(digitalPinToInterrupt(ZCDinterruptPin), acon, FALLING); // attach Interrupt at PIN2
}

void loop() {

  if (irrecv.decode(&results)) {
    if (results.value == 0XFFFFFFFF)
      results.value = key_value;

    if ((results.value == 0x88C0051)) {                                     // Button 1
      // TODO
    }

    if ((results.value == 0x88C000C)) {                                     // Button 2 -Speed1
      speed1 = true;
      speed2 = false;
      speed3 = false;
    }
    if ((results.value == 0x8810089)) {                                     // Button 3 -Speed2
      speed1 = false;
      speed2 = true;
      speed3 = false;
    }
    if ((results.value == 0x8808350)) {                                     // Button 4 -Speed3
      speed1 = false;
      speed2 = false;
      speed3 = true;
    }
    key_value = results.value;
    irrecv.resume();
  }

  if (speed1 == true && speed2 == false && speed3 == false) { // speed 1
    x = 6600;
    attachInterrupt(digitalPinToInterrupt(ZCDinterruptPin), acon, FALLING); // attach Interrupt at PIN2
  }
  if (speed1 == false && speed2 == true && speed3 == false) { // speed 2
    x = 4800;
    attachInterrupt(digitalPinToInterrupt(ZCDinterruptPin), acon, FALLING); // attach Interrupt at PIN2
  }
  if (speed1 == false && speed2 == false && speed3 == true) { // speed 3
    x = 2500;
    attachInterrupt(digitalPinToInterrupt(ZCDinterruptPin), acon, FALLING); // attach Interrupt at PIN2
  }
}



void acon()
{
    detachInterrupt(digitalPinToInterrupt(ZCDinterruptPin));
    delayMicroseconds(x); //
    digitalWrite(triacPulse, HIGH);
    delayMicroseconds(50);  //delay 50 uSec on output pulse to turn on triac
    digitalWrite(triacPulse, LOW);
}