Saving Processed Data from an InvenSense MPU9150 to an SD card

[DBROWN13119]

I want to save processed data (calibrated acceleration and fused euler angles) generated from the Arduino9150 sketch from https://github.com/richards-tech/MPU9150Lib to an SD card. My current sketch has attempted to combine the Arduino9150 sketch and example Datalogger sketch provided with the Arduino SD library.

The system hardware includes an Arduino Mega 2560 board, Invensense MPU9150 breakout board and Sparkfun microSD shield.

The desired format of the data saved to the SD card is a CSV file with six columns. The first three columns should have the calibrated accelerations in the x, y and z directions (included in sketch as MPU.m_calAccel) and the second three columns should have the fused euler angles in the x, y and z directions (included in sketch as MPU.m_fusedEulerPose).

Currently the sketch works to display these outputs on the Arduino serial monitor but I cannot get the data to save to the SD card correctly. I have checked the library where the sketch reads the processed results from (MPU9150Lib.h) and from what I can tell the processed data is in the form of floating point type vectors with three columns (libraries available from https://github.com/richards-tech/MPU9150Lib). I am trying to append each column to a string and then write the string to the SD card.

Below is my code as it currently stands, with all comments stating what I want to achieve within each portion of the sketch (some comment from original code from https://github.com/richards-tech/MPU9150Lib). When I try to verify it I get the error message: "call of overloaded 'printVector(short int&)' is ambiguous".

#include <Wire.h>
#include "I2Cdev.h"
#include "MPU9150Lib.h"
#include "CalLib.h"
#include <dmpKey.h>
#include <dmpmap.h>
#include <inv_mpu.h>
#include <inv_mpu_dmp_motion_driver.h>
#include <EEPROM.h>
#include <SD.h>  //Includes SD shield library

//  DEVICE_TO_USE selects whether the IMU at address 0x68 (default) or 0x69 is used
//    0 = use the device at 0x68
//    1 = use the device at ox69

#define  DEVICE_TO_USE    0


MPU9150Lib MPU;                                              // the MPU object


//  MPU_UPDATE_RATE defines the rate (in Hz) at which the MPU updates the sensor data and DMP output

#define MPU_UPDATE_RATE  (20)


//  MAG_UPDATE_RATE defines the rate (in Hz) at which the MPU updates the magnetometer data
//  MAG_UPDATE_RATE should be less than or equal to the MPU_UPDATE_RATE

#define MAG_UPDATE_RATE  (10)


//  MPU_MAG_MIX defines the influence that the magnetometer has on the yaw output.
//  The magnetometer itself is quite noisy so some mixing with the gyro yaw can help
//  significantly. Some example values are defined below:

#define  MPU_MAG_MIX_GYRO_ONLY          0                   // just use gyro yaw
#define  MPU_MAG_MIX_MAG_ONLY           1                   // just use magnetometer and no gyro yaw
#define  MPU_MAG_MIX_GYRO_AND_MAG       10                  // a good mix value (uses this value)
#define  MPU_MAG_MIX_GYRO_AND_SOME_MAG  50                  // mainly gyros with a bit of mag correction 


//  MPU_LPF_RATE is the low pas filter rate and can be between 5 and 188Hz

#define MPU_LPF_RATE   40


//  SERIAL_PORT_SPEED defines the speed to use for the debug serial port

#define  SERIAL_PORT_SPEED  115200


// Chip Select pin is tied to pin 8 on the SparkFun SD Card Shield 
//(may have to connect to different Mega pin though

const int chipSelect = 8;





void setup()
{
// Serial port information
  Serial.begin(SERIAL_PORT_SPEED);
  Serial.print("Arduino9150 starting using device "); Serial.println(DEVICE_TO_USE);
 
 
// Start up the MPU device
  Wire.begin();
  MPU.selectDevice(DEVICE_TO_USE);                        // only really necessary if using device 1
  MPU.init(MPU_UPDATE_RATE, MPU_MAG_MIX_GYRO_AND_MAG, MAG_UPDATE_RATE, MPU_LPF_RATE);   // start the MPU
  
  
  //Start up SD shield
   Serial.print("Initializing SD card...");
  
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
   pinMode(chipSelect, OUTPUT);

  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    
    Serial.println("Card failed, or not present");
    // don't do anything more:
    return;
  
  Serial.println("card initialized.");
  }  

 
 // Writes open the csv file, prepares column headings
  File dataFile = SD.open("DATA.csv", FILE_WRITE);
  
  if (dataFile) {
    dataFile.println(",,,,,");
    
    String header = "AccX,AccY,AccZ,AngleX,AngleY,AngleZ";
    dataFile.println(header);
    dataFile.close();
    
    Serial.println();
    Serial.println(header);
  } else {
  Serial.println("Couldn't open log file");
  } 
 
}



void loop()
{  
    // make a string for assembling the data to log:
    String dataString = "";
  
     
// Reads data from MPU9150Lib and appends it to the string
  if (MPU.read())              // get the latest data if ready yet
  {                                        
    float AccX = MPU.printVector(MPU.m_calAccel[0]);
    dataString += String(AccX);
    
    float AccY = MPU.printVector(MPU.m_calAccel[1]);
    dataString += String(AccY);
    
    float AccZ = MPU.printVector(MPU.m_calAccel[2]);
    dataString += String(AccZ);
    
    float AngleX = MPU.printAngles(MPU.m_fusedEulerPose[0]);
    dataString += String(AccX);
    
    float AngleY = MPU.printAngles(MPU.m_fusedEulerPose[1]);
    dataString += String(AccY);
    
    float AngleZ = MPU.printAngles(MPU.m_fusedEulerPose[2]);
    dataString += String(AccZ);
    
    
}
  
  
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  File dataFile = SD.open("DATA.csv", FILE_WRITE);

  // if the file is available, write to it:
  if (dataFile) {
    dataFile.println(dataString);
    dataFile.close();
    // print to the serial port too:
    Serial.println(dataString);
  }  
  
  // if the file isn't open, pop up an error:
  else {
    Serial.println("error opening datalog.txt");
  } 
  

}