KY-040 Rotary encoder module

Rotary encoder 20 Pulse. With the buttons on the rotary encoder.

Link >>> http://forum.arduino.cc/index.php?topic=242356.0

Link >>> http://bigdanzblog.wordpress.com/2014/08/16/using-a-ky040-rotary-encoder-with-arduino/

Example Code.

volatile boolean TurnDetected;

volatile boolean up;

const int PinCLK=2;                   // Used for generating interrupts using CLK signal

const int PinDT=3;                    // Used for reading DT signal

const int PinSW=4;                    // Used for the push button switch

void isr ()  {                    // Interrupt service routine is executed when a HIGH to LOW transition is detected on CLK

 if (digitalRead(PinCLK))

   up = digitalRead(PinDT);

 else

   up = !digitalRead(PinDT);

 TurnDetected = true;

}

void setup ()  {

 pinMode(PinCLK,INPUT);

 pinMode(PinDT,INPUT);  

 pinMode(PinSW,INPUT);

 digitalWrite(PinCLK, HIGH);

 digitalWrite(PinDT, HIGH);

 digitalWrite(PinSW, HIGH);

 attachInterrupt (0,isr,FALLING);   // interrupt 0 is always connected to pin 2 on Arduino UNO

 Serial.begin (9600);

 Serial.println("Start");

}

void loop ()  {

 static long virtualPosition=0;    // without STATIC it does not count correctly!!!

 if (!(digitalRead(PinSW))) {      // check if pushbutton is pressed

   virtualPosition=0;              // if YES, then reset counter to ZERO

   Serial.print ("Reset = ");      // Using the word RESET instead of COUNT here to find out a buggy encoder

   Serial.println (virtualPosition);

 }  

 if (TurnDetected)  {    // do this only if rotation was detected

   if (up)

     virtualPosition++;

   else

     virtualPosition--;

   TurnDetected = false;          // do NOT repeat IF loop until new rotation detected

   Serial.print ("Count = ");  

   Serial.println (virtualPosition);

 }

}