//http://domoticx.com/arduino-rotary-encoder-keyes-ky-040/

int clock = 2;             // Define encoder pin A
int data = 3;              // Define encoder pin B
int count = 0;             // pre-init the count to zero
int c = LOW;               // pre-init the state of pin A low
int cLast = LOW;           // and make its last val the same - ie no change
int d = LOW;               // and make the data val low as well
 
void setup() {
  pinMode (clock,INPUT);  // setup the pins as inputs
  pinMode (data,INPUT);
  Serial.begin (9600);    // and give some serial debugging
}
 
void loop() {
  c = digitalRead(clock); // read pin A as clock
  d = digitalRead(data);  // read pin B as data
 
  if (c != cLast) {       // clock pin has changed value... now we can do stuff
    d = c^d;              // work out direction using an XOR
    if ( d ) {
      count--;            // non-zero is Anti-clockwise
    }else{
      count++;            // zero is therefore anti-clockwise
    }
    Serial.print ("Jog:: count:");
    Serial.println(count);
    cLast = c;            // store current clock state for next pass
  }
}