arduino stuff

#define MIDVAL 128
#define FULLREV 240.0
int digital1 = 0;
int digital2 = 0;
int previousValue = 0;
int totalParts = 0;
bool readAlready = false;

int pTotal = 0;
int timer = 0;
double intervalStart = 0;
double intervalEnd = 0;
int previousTime = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(0, INPUT);
  pinMode(1, INPUT);
  Serial.begin(115200);
  previousValue = readCyclePart(digital1, digital2);
  readAlready = true;
  intervalStart = millis();
}

void loop() {
  timer = millis();
  digital1 = digitalRead(2);
  digital2 = digitalRead(3);
  countStep();
  if(timer % 200 == 0 && millis() != previousTime) {
    previousTime = millis();
    //Serial.print("Parts: ");
    Serial.print(totalParts);
    double rpm = calculateRpm();
    //Serial.print(", RPM: ");
    Serial.print(" ");
    Serial.print(rpm);
    Serial.println();
    totalParts = 0;
  }
  pTotal = totalParts;
}

int readCyclePart(int a, int b){
  bool boolA = a==HIGH;
  bool boolB = b==HIGH;

  if(!boolA && !boolB)
    return 0;
  else if(boolA && !boolB)
    return 1;
  else if(boolA && boolB)
    return 2;
  else if(!boolA && boolB)
    return 3;
}

void countStep(){
  int currentValue = readCyclePart(digital1, digital2);
  int diff = 0;
  if(previousValue > currentValue){
    diff = currentValue + 4 - previousValue;
  }else{
    diff = currentValue - previousValue;
  }
  totalParts += diff;
  previousValue = currentValue;
}

double calculateRpm(){
    intervalEnd = millis();
    double elapsedTime = intervalEnd - intervalStart;
    double minuteScaleFactor = 60000/elapsedTime;
    double rotationalFraction = totalParts/FULLREV;
    double rpm = rotationalFraction/elapsedTime*minuteScaleFactor;
    intervalStart = millis();
    return rpm;
}