KY-040 Rotary Encoder (WH-040)

The Rotary encoder can be counted by rotating forward and reverse direction during rotation of the output pulse frequency.

Pin pitch: 2.54mm

int redPin = 2;
int yellowPin = 3;
int greenPin = 4;
int aPin = 6;
int bPin = 7;
int buttonPin = 5;
int state = 0;
int longPeriod = 5000; // Time at green or red
int shortPeriod = 700; // Time period when changing
int targetCount = shortPeriod;
int count = 0;

void setup() {
pinMode(aPin, INPUT);
pinMode(bPin, INPUT);
pinMode(buttonPin, INPUT);
pinMode(redPin, OUTPUT);
pinMode(yellowPin, OUTPUT);
pinMode(greenPin, OUTPUT);
}
void loop() {
count++;
if (digitalRead(buttonPin)) {
setLights (HIGH, HIGH, HIGH);
} else {
int change = getEncoderTurn ();
int newPeriod = longPeriod + (change * 1000);
if (newPeriod >= 1000 && newPeriod <= 10000) {
longPeriod = newPeriod;
}
if (count> targetCount) {
setState ();
count = 0;
}
}
delay(1);
}
int getEncoderTurn () {
// Return -1, 0, or +1
static int oldA = LOW;
static int oldB = LOW;
int result = 0;
int newA = digitalRead(aPin);
int newB = digitalRead(bPin);
if (newA != oldA || newB != oldB) {
//Something has changed
if (oldA == LOW && newA == HIGH) {
result = - (oldB * 2 - 1);
}
}
oldA = newA;
oldB = newB;
return result;
}
int setState () {
if (state == 0) {
setLights (HIGH, LOW, LOW);
targetCount = longPeriod;
state = 1;
} else if (state == 1) {
setLights (HIGH, HIGH, LOW);
targetCount = shortPeriod;
state = 2;
} else if (state == 2) {
setLights (LOW, LOW, HIGH);
targetCount = longPeriod;
state = 3;
} else if (state == 3) {
setLights (LOW, HIGH, LOW);
targetCount = shortPeriod;
state = 0;
}
}
void setLights (int red, int yellow, int green) {
digitalWrite(redPin, red);
digitalWrite(yellowPin, yellow);
digitalWrite(greenPin, green);
}