View source for Sunfounder Rotery Encoder

[[File:Fgvr.jpg]]

 //Rotary Encoder
 /*You will see the angular displacement of the rotary encoder printed on Serial Monitor.
 When you turn the rotary encoder clockwise, the angular displacement is increased;
 when turn it counterclockwise, the displacement is decreased.
 If you press the switch on the rotary encoder, the readings will return to zero.*/
 //Email: support@sunfounder.com
 //Website: www.sunfounder.com
 //2015.5.7
 const int clkPin= 2; //the clk attach to pin 2
 const int dtPin= 3; //the dt pin attach to pin 3
 const int swPin= 4 ;//the sw pin attach to pin 4
 int encoderVal = 0;
 void setup()
 {
 //set clkPin,dePin,swPin as INPUT
 pinMode(clkPin, INPUT);
 pinMode(dtPin, INPUT);
 pinMode(swPin, INPUT);
 digitalWrite(swPin, HIGH);
 Serial.begin(9600); // initialize serial communications at 9600 bps
 }
 void loop()
 {
 int change = getEncoderTurn();//
 encoderVal = encoderVal + change;
 if(digitalRead(swPin) == LOW)//if button pull down
 {
 encoderVal = 0;
 }
 Serial.println(encoderVal);
 }
 int getEncoderTurn(void)
 {
 static int oldA = HIGH; //set the oldA as HIGH
 static int oldB = HIGH; //set the oldB as HIGH
 int result = 0;
 int newA = digitalRead(clkPin);//read the value of clkPin to newA
 int newB = digitalRead(dtPin);//read the value of dtPin to newB
 if (newA != oldA || newB != oldB) //if the value of clkPin or the dtPin has changed
 {
 // something has changed
 if (oldA == HIGH && newA == LOW)
 {
 result = (oldB * 2 - 1);
 }
 }
 oldA = newA;
 oldB = newB;
 return result;
 }