OK. For the third time:
Then this question:
and what is connected to pins 2 & 3 ?
Also: how are you determining that an interrupt has not been detected ?
Ignore the last test code change I gave you and temporarily replace your loop with this which will determine if interrupts are working or not or maybe point to a logic error in your code.
void loop ()
{
if (ang == false )
{
Serial.println("Interrupt detected");
ang = true ;
}
}