Inertial Calculator

#define ENCODER_PIN_A  2
#define ENCODER_PIN_B  3
#define TRIGGER_PIN 18

volatile long encoder0Pos = 0;
long newposition;
long oldposition = 0;
unsigned long newtime;
unsigned long oldtime = 0;
double vel = 0;

boolean timerRunning = false;
boolean calcStarted = false;
long startTime = 0;

void setup(){
  Serial.begin (9600);
  Serial.println("start");                // a personal quirk

  pinMode(ENCODER_PIN_A, INPUT);
  digitalWrite(ENCODER_PIN_A, HIGH);       // turn on pullup resistor
  pinMode(ENCODER_PIN_B, INPUT);
  digitalWrite(ENCODER_PIN_B, HIGH);       // turn on pullup resistor
  pinMode(TRIGGER_PIN, INPUT);
  attachInterrupt(0, encodeCount, CHANGE);

  attachInterrupt(5, beginTiming, FALLING);


}

void loop(){
  noInterrupts();
  newtime = millis();
  newposition = encoder0Pos;
  interrupts();
  vel = (double(newposition-oldposition)) /(double(newtime-oldtime));
  oldposition = newposition;
  oldtime = newtime;
  Serial.print(vel);
  Serial.print(", ");
  Serial.print(millis()-startTime);
  if(timerRunning){
    if(vel == 0.00){
       Serial.print(", ");
       Serial.print("Stopped Here");
     }
  }
  Serial.println();

}

void beginTiming(){
  if(!timerRunning){
    //startTime = millis();
  }
  timerRunning = true;
}

void encodeCount(){
  if (digitalRead(ENCODER_PIN_A) == digitalRead(ENCODER_PIN_B)) {
    encoder0Pos++;
  } else {
    encoder0Pos--;
  }
}