 
 // ******************* INTERRUPT EVENTS ******************* 
 void triggerCount() {
-  tickCount = tickCount + 1;
+  tickCount = tickCount + 1.0;
   millisSinceLastTick = millis();
 }
 


void setup() {
  Serial.begin(115200);
  Serial.println(WHEEL_CIRCUMFERENCE);
  
  pinMode(HALL_SENSOR, INPUT_PULLUP);
  attachInterrupt(0,triggerCount, FALLING);

  // How many CM per second we've traveled, based on wheel circumference and number of wheel turns since last check
  double cmps =  (1000/(millisSinceLastTick - currentMillis)) * WHEEL_CIRCUMFERENCE * tickCount;
  // reset counts
  tickCount = 0.0;
  currentMillis = millisSinceLastTick;
  if (isnan(cmps)) {
    cmps = 0.0; 
  }
  return cmps/10000.0 * 360.0;
}

double calculateMPH() {
