// Rotary Encoder Inputs
#define CLK 2 // Output A
#define DT 3 // Output B
 
int counter = 0;
int currentStateCLK;
int lastStateCLK;
String currentDir ="";
unsigned long lastButtonPress = 0;
 
void setup() {
 
  // Set encoder pins as inputs
  pinMode(CLK,INPUT);
  pinMode(DT,INPUT);

  // Setup Serial Monitor
  Serial.begin(9600);
 
  // Read the initial state of CLK
  lastStateCLK = digitalRead(CLK);

  // Adding interrupt on a CHANGE event
  // This is because our original code only cares when the state of CLK changes 
  attachInterrupt(digitalPinToInterrupt(CLK), CalcDirection, CHANGE);
}
 
void loop()
{}

void CalcDirection() {
 
  // Read the current state of CLK
  currentStateCLK = digitalRead(CLK);
 
  // If last and current state of CLK are different, then pulse occurred
  // React to only 1 state change to avoid double count
  if (currentStateCLK != lastStateCLK  && currentStateCLK == 1){
  //if ((lastStateCLK == LOW) && (currentStateCLK == HIGH)){
    // If the DT state is different than the CLK state then
    // the encoder is rotating CCW so decrement
    if (digitalRead(DT) != currentStateCLK) {
    //if (digitalRead(DT) == HIGH){
      counter ++;
      currentDir ="CW";
    } else {
      // Encoder is rotating CCW so decrement
      counter --;
      currentDir ="CCW";
    }
 
    Serial.print("Direction: ");
    Serial.print(currentDir);
    Serial.print(" | Counter: ");
    Serial.println(counter);
 }
 //}
 
  // Remember last CLK state
  lastStateCLK = currentStateCLK;
 
}