// Rotary Encoder Module connections
const int PinSW=3;   // Rotary Encoder Switch
const int PinDT=4;    // DATA signal
const int PinCLK=2;    // CLOCK signal

// Variables to debounce Rotary Encoder
long TimeOfLastDebounce = 0;
int DelayofDebounce = 0.01;

// Store previous Pins state
int PreviousCLK;
int PreviousDATA;

int displaycounter=0; // Store current counter value

void isr ()
  {

  // If enough time has passed check the rotary encoder
  if ((millis() - TimeOfLastDebounce) > DelayofDebounce) {

    check_rotary();  // Rotary Encoder check routine below

    PreviousCLK=digitalRead(PinCLK);
    PreviousDATA=digitalRead(PinDT);

    TimeOfLastDebounce=millis();  // Set variable to current millis() timer
  }

  // Check if Rotary Encoder switch was pressed
  if (digitalRead(PinSW) == LOW) {
    displaycounter=0;  // Reset counter to zero
  }

  }



void setup() {

  // Set the Switch pin to use Arduino PULLUP resistors
  pinMode(PinSW, INPUT_PULLUP);
  pinMode(PinCLK,INPUT_PULLUP);
  pinMode(PinDT,INPUT_PULLUP);
  Serial.begin(115200);
  Serial.println("Encoder");
}

void loop() {

}

// Check if Rotary Encoder was moved
void check_rotary() {

 if ((PreviousCLK == 0) && (PreviousDATA == 1)) {
    if ((digitalRead(PinCLK) == 1) && (digitalRead(PinDT) == 0)) {
      displaycounter++;
    }
    if ((digitalRead(PinCLK) == 1) && (digitalRead(PinDT) == 1)) {
      displaycounter--;
    }
  }

if ((PreviousCLK == 1) && (PreviousDATA == 0)) {
    if ((digitalRead(PinCLK) == 0) && (digitalRead(PinDT) == 1)) {
      displaycounter++;
    }
    if ((digitalRead(PinCLK) == 0) && (digitalRead(PinDT) == 0)) {
      displaycounter--;
    }
  }

if ((PreviousCLK == 1) && (PreviousDATA == 1)) {
    if ((digitalRead(PinCLK) == 0) && (digitalRead(PinDT) == 1)) {
      displaycounter++;
    }
    if ((digitalRead(PinCLK) == 0) && (digitalRead(PinDT) == 0)) {
      displaycounter--;
    }
  }

if ((PreviousCLK == 0) && (PreviousDATA == 0)) {
    if ((digitalRead(PinCLK) == 1) && (digitalRead(PinDT) == 0)) {
      displaycounter++;
    }
    if ((digitalRead(PinCLK) == 1) && (digitalRead(PinDT) == 1)) {
      displaycounter--;

    }
  }
          Serial.print("Counter = "); Serial.println(displaycounter);
 }