microcontroller - Arduino 230v Light bulb dimming

Hey guys i have done a lot of research and testing on different circuits for 230v(50hz) or 220v light dimming, but i cant get my arduino to dim my light. This is the last thing i tried.

made this circuit : Circuit and Code Link

Code which i tried:

int AC_LOAD = 3;    // Output to Opto Triac pin
int dimming = 128;  // Dimming level (0-128)  0 = ON, 128 = OFF


void setup()
{
  pinMode(AC_LOAD, OUTPUT);       // Set the AC Load as output
  attachInterrupt(0, zero_crosss_int, RISING);  // Choose the zero cross interrupt # from the table above
}

void zero_crosss_int()  // function to be fired at the zero crossing to dim the light
{
  // Firing angle calculation :: 50Hz-> 10ms (1/2 Cycle)
  // (10000us - 10us) / 128 = 75 (Approx)

  int dimtime = (75*dimming);      
  delayMicroseconds(dimtime);    // Off cycle
  digitalWrite(AC_LOAD, HIGH);   // triac firing
  delayMicroseconds(10);         // triac On propogation delay
  digitalWrite(AC_LOAD, LOW);    // triac Off
}

void loop()
{
  dimming = 128; 

  delay(100);
  dimming = 75;  
  delay(100);
  dimming = 25;  
  delay(100);

}