Dimmer

#define triacPin 3
#define POT A2
#define ZCD 1
int x = 0;

void setup() {

  pinMode(ZCD, INPUT_PULLUP);
  pinMode(A0, INPUT);
  pinMode(triacPin, OUTPUT);
}

void loop() {


  int y = analogRead(A0);
  x = map(y, 0, 1024, 200, 7200);
  attachInterrupt(0, ISR_F, FALLING); // attach Interrupt at PIN2
}



void ISR_F()
{
  delayMicroseconds(x);
  digitalWrite(triacPin, HIGH);
  delayMicroseconds(50);
  digitalWrite(triacPin, LOW);
}