void CalibrateData::callbackAccelGyro(const sensor_msgs::ImuConstPtr & msg)
{
  Eigen::Vector3d accel_raw;
  Eigen::Vector3d accel_cal;
  Eigen::Vector3d gyro_raw;
  Eigen::Vector3d gyro_cal;

  accel_raw(0) = msg->linear_acceleration.x;
  accel_raw(1) = msg->linear_acceleration.y;
  accel_raw(2) = msg->linear_acceleration.z;
  gyro_raw(0) = msg->angular_velocity.x;
  gyro_raw(1) = msg->angular_velocity.y;
  gyro_raw(2) = msg->angular_velocity.z;

  accel_cal = calibrate(accel_raw,
                        accel_alignment_matrix_,
                        accel_sensitivity_matrix_,
                        accel_offset_vector_);
  gyro_cal = calibrate(gyro_raw,
                       gyro_alignment_matrix_,
                       gyro_sensitivity_matrix_,
                       gyro_offset_vector_);

  sensor_msgs::Imu imu_msg = *msg;
  imu_msg.linear_acceleration.x = accel_cal(0);
  imu_msg.linear_acceleration.y = accel_cal(1);
  imu_msg.linear_acceleration.z = accel_cal(2);
  imu_msg.angular_velocity.x = gyro_cal(0) * M_PI / 180.0;
  imu_msg.angular_velocity.y = gyro_cal(1) * M_PI / 180.0;
  imu_msg.angular_velocity.z = gyro_cal(2) * M_PI / 180.0;

  imu_pub_.publish(imu_msg);
}
// Set baseline MPU readings at init
void FC_IMU::set_baseline() {
  int16_t tmp_acc[3] = {0, 0, 0};
  int16_t tmp_gyro[3] = {0, 0, 0};
  
  int32_t acc_tot[3] = {0, 0, 0};
  int32_t gyro_tot[3] = {0, 0, 0};
  
  for (int i = 20; i --> 0;) {
    accel_raw(tmp_acc);
    gyro_raw(tmp_gyro);
    
    for (int j = 0; j < 3; j++) {
      acc_tot[j]  += (int32_t)tmp_acc[j];
      gyro_tot[j] += (int32_t)tmp_gyro[j];
    }
    // Serial.print("Acc: ");
    // Serial.print(tmp_acc[0]);
    // Serial.print(" ");
    // Serial.print(tmp_acc[1]);
    // Serial.print(" ");
    // Serial.print(tmp_acc[2]);
    // Serial.print(" Gyro: ");
    // Serial.print(tmp_gyro[0]);
    // Serial.print(" ");
    // Serial.print(tmp_gyro[1]);
    // Serial.print(" ");
    // Serial.println(tmp_gyro[2]);
    delay(100);
  }
  // Serial.print("Acc: ");
  // Serial.print(acc_tot[0]);
  // Serial.print(" ");
  // Serial.print(acc_tot[1]);
  // Serial.print(" ");
  // Serial.print(acc_tot[2]);
  // Serial.print(" Gyro: ");
  // Serial.print(gyro_tot[0]);
  // Serial.print(" ");
  // Serial.print(gyro_tot[1]);
  // Serial.print(" ");
  // Serial.println(gyro_tot[2]);
  for (int i = 0; i < 3; i++) {
    _accel_baseline[i] = (int16_t)(acc_tot[i] / 20);
    _gyro_baseline[i]  = (int16_t)(gyro_tot[i] / 20);
  }
}