int beepPin = 9;

int toneValue = 50;

int rotaryPinA = 1;
int rotaryPinB = 2;

int rotaryReadA;
int rotaryReadB;

int rotaryReadAPrev = 0;

unsigned long currentTime;
unsigned long loopTime;

void setup()
{
  Serial.begin(9600);
  pinMode(beepPin, OUTPUT);

  pinMode(rotaryPinA, INPUT);
  pinMode(rotaryPinB, INPUT);

  currentTime = millis();
  loopTime = currentTime;
}

void loop()
{
  currentTime = millis();

  if (currentTime >= (loopTime + 5))
  {

    rotaryReadA = digitalRead(rotaryPinA);
    rotaryReadB = digitalRead(rotaryPinB);

    Serial.print("A");
    Serial.println(rotaryReadA);
    Serial.print("B");
    Serial.println(rotaryReadB);

    if ((!rotaryReadA) && (rotaryReadAPrev))
    {
      if (rotaryReadB)
      {
        toneValue += 50;
        Serial.println("+");
      }
      else
      {
        toneValue -= 50;
        Serial.println("-");
      }
    }

    rotaryReadAPrev = rotaryReadA;
    beep(toneValue, 100);
    loopTime = currentTime;

  }
}

void beep(int toneValue, int delayTime)
{
  analogWrite(beepPin, toneValue);
  delay(delayTime);

  analogWrite(beepPin, 0);
  delay(delayTime * 15);
}