 #include <Adafruit_MMA8451.h>
 #include <Adafruit_Sensor.h>
 
+// Scooter constants
+const float WHEEL_RADIUS = 6.0; // in cm
+const float WHEEL_CIRCUMFERENCE = 2 * WHEEL_RADIUS * PI;
+double kph = 0.0;
+
 // Hall effect sensor read pin, make it an interrupt pin so we catch all revolutions
 const byte HALL_SENSOR = 2;
 boolean isHallSensorTriggered = false;
 int tickCount = 0;
+int currentMillis = 0;
 int millisSinceLastTick = 0;
 
 // 16x2 LCD display pins

  millisSinceLastTick = millis();
}


  mma.getEvent(&event);
  
  lcd.clear();
  
  kph = calculateKPH();
  
  lcd.print("Spd: ");
  lcd.print(kph);
  lcd.print("kph");
  
  lcd.setCursor(0,1);
  lcd.print("AccY:");
  lcd.print(event.acceleration.y);
  lcd.print(" m/s^2");
  
  // using blocking delay debounces the accelerometer and gives the display time to refresh
  delay(250);
}
