// Accelerometer Settings
#define RA_SIZE 3  // number of readings to include in running average of accelerometer readings

// Accelerometer Class -- extends the LSM303 Library to support reading and averaging the x-y acceleration 
//   vectors from the onboard LSM303DLHC accelerometer/magnetometer
class Accelerometer : public LSM303
{
  typedef struct acc_data_xy
  {
    unsigned long timestamp;
    int x;
    int y;
    float dir;
  } acc_data_xy;
  
  public: 
	Accelerometer() : ra_x(RA_SIZE), ra_y(RA_SIZE) {};
    ~Accelerometer() {};
    void begin(void) {
		Wire.begin();
		init();
		enable();
	};
    void enable(void);
    void getLogHeader(void);
    void readAcceleration(unsigned long timestamp);
    float len_xy() const;
    float dir_xy() const;
    int x_avg(void) const;
    int y_avg(void) const;
    long ss_xy_avg(void) const;
    float dir_xy_avg(void) const;
  private:
    acc_data_xy last;
    RunningAverage<int> ra_x;
    RunningAverage<int> ra_y;   
};