/***************************************************************************************************************
 * Razor AHRS Firmware v1.4.0
 * 9 Degree of Measurement Attitude and Heading Reference System
 * for Sparkfun "9DOF Razor IMU" (SEN-10125 and SEN-10736)
 * and "9DOF Sensor Stick" (SEN-10183, 10321 and SEN-10724)
 *
 * Released under GNU GPL (General Public License) v3.0
 * Copyright (C) 2011 Quality & Usability Lab, Deutsche Telekom Laboratories, TU Berlin
 *
 * Infos, updates, bug reports and feedback:
 *     http://dev.qu.tu-berlin.de/projects/sf-razor-9dof-ahrs
 *
 *
 * History:
 *   * Original code (http://code.google.com/p/sf9domahrs/) by Doug Weibel and Jose Julio,
 *     based on ArduIMU v1.5 by Jordi Munoz and William Premerlani, Jose Julio and Doug Weibel. Thank you!
 *
 *   * Updated code (http://groups.google.com/group/sf_9dof_ahrs_update) by David Malik (david.zsolt.malik@gmail.com)
 *     for new Sparkfun 9DOF Razor hardware (SEN-10125).
 *
 *   * Updated and extended by Peter Bartz (peter-bartz@gmx.de):
 *     * v1.3.0
 *       * Cleaned up, streamlined and restructured most of the code to make it more comprehensible.
 *       * Added sensor calibration (improves precision and responsiveness a lot!).
 *       * Added binary yaw/pitch/roll output.
 *       * Added basic serial command interface to set output modes/calibrate sensors/synch stream/etc.
 *       * Added support to synch automatically when using Rovering Networks Bluetooth modules (and compatible).
 *       * Wrote new easier to use test program (using Processing).
 *       * Added support for new version of "9DOF Razor IMU": SEN-10736.
 *       --> The output of this code is not compatible with the older versions!
 *       --> A Processing sketch to test the tracker is available.
 *     * v1.3.1
 *       * Initializing rotation matrix based on start-up sensor readings -> orientation OK right away.
 *       * Adjusted gyro low-pass filter and output rate settings.
 *     * v1.3.2
 *       * Adapted code to work with new Arduino 1.0 (and older versions still).
 *     * v1.3.3
 *       * Improved synching.
 *     * v1.4.0
 *       * Added support for SparkFun "9DOF Sensor Stick" (versions SEN-10183, SEN-10321 and SEN-10724).
 *
 * TODOs:
 *   * Allow optional use of EEPROM for storing and reading calibration values.
 *   * Use self-test and temperature-compensation features of the sensors.
 *   * Add binary output of unfused sensor data for all 9 axes.
 ***************************************************************************************************************/

/*
  "9DOF Razor IMU" hardware versions: SEN-10125 and SEN-10736

 ATMega328@3.3V, 8MHz

 ADXL345  : Accelerometer
 HMC5843  : Magnetometer on SEN-10125
 HMC5883L : Magnetometer on SEN-10736
 ITG-3200 : Gyro

 Arduino IDE : Select board "Arduino Pro or Pro Mini (3.3v, 8Mhz) w/ATmega328"
 */

/*
  "9DOF Sensor Stick" hardware versions: SEN-10183, SEN-10321 and SEN-10724

 ADXL345  : Accelerometer
 HMC5843  : Magnetometer on SEN-10183 and SEN-10321
 HMC5883L : Magnetometer on SEN-10724
 ITG-3200 : Gyro
 */

/*
  Axis definition (differs from definition printed on the board!):
 X axis pointing forward (towards the short edge with the connector holes)
 Y axis pointing to the right
 and Z axis pointing down.

 Positive yaw   : clockwise
 Positive roll  : right wing down
 Positive pitch : nose up

 Transformation order: first yaw then pitch then roll.
 */

/*
  Commands that the firmware understands:

 "#o<param>" - Set output parameter. The available options are:
 "#o0" - Disable continuous streaming output.
 "#o1" - Enable continuous streaming output.
 "#ob" - Output angles in binary format (yaw/pitch/roll as binary float, so one output frame
 is 3x4 = 12 bytes long).
 "#ot" - Output angles in text format (Output frames have form like "#YPR=-142.28,-5.38,33.52",
 followed by carriage return and line feed [\r\n]).
 "#os" - Output (calibrated) sensor data of all 9 axes in text format. One frame consist of
 three lines - one for each sensor.
 "#oc" - Go to calibration output mode.
 "#on" - When in calibration mode, go on to calibrate next sensor.
 "#oe0" - Disable error message output.
 "#oe1" - Enable error message output.

 "#f" - Request one output frame - useful when continuous output is disabled and updates are
 required in larger intervals only.
 "#s<xy>" - Request synch token - useful to find out where the frame boundaries are in a continuous
 binary stream or to see if tracker is present and answering. The tracker will send
 "#SYNCH<xy>\r\n" in response (so it's possible to read using a readLine() function).
 x and y are two mandatory but arbitrary bytes that can be used to find out which request
 the answer belongs to.

 ("#C" and "#D" - Reserved for communication with optional Bluetooth module.)

 Newline characters are not required. So you could send "#ob#o1#s", which
 would set binary output mode, enable continuous streaming output and request
 a synch token all at once.

 The status LED will be on if streaming output is enabled and off otherwise.

 Byte order of binary output is little-endian: least significant byte comes first.
 */



/*****************************************************************/
/*********** USER SETUP AREA! Set your options heredall! *************/
/*****************************************************************/

// HARDWARE OPTIONS
/*****************************************************************/
// Select your hardware here by uncommenting one line!
//#define HW__VERSION_CODE 10125 // SparkFun "9DOF Razor IMU" version "SEN-10125" (HMC5843 magnetometer)
//#define HW__VERSION_CODE 10736 // SparkFun "9DOF Razor IMU" version "SEN-10736" (HMC5883L magnetometer)
//#define HW__VERSION_CODE 10183 // SparkFun "9DOF Sensor Stick" version "SEN-10183" (HMC5843 magnetometer)
//#define HW__VERSION_CODE 10321 // SparkFun "9DOF Sensor Stick" version "SEN-10321" (HMC5843 magnetometer)
#define HW__VERSION_CODE 10724 // SparkFun "9DOF Sensor Stick" version "SEN-10724" (HMC5883L magnetometer)


// OUTPUT OPTIONS
/*****************************************************************/
// Set your serial port baud rate used to send out data here!
#define OUTPUT__BAUD_RATE 115200

// Sensor data output interval in milliseconds
// This may not work, if faster than 20ms (=50Hz)
// Code is tuned for 20ms, so better leave it like that
#define OUTPUT__DATA_INTERVAL 20  // in milliseconds

// Output mode
#define OUTPUT__MODE_CALIBRATE_SENSORS 0 // Outputs sensor min/max values as text for manual calibration
#define OUTPUT__MODE_ANGLES_TEXT 1 // Outputs yaw/pitch/roll in degrees as text
#define OUTPUT__MODE_ANGLES_BINARY 2 // Outputs yaw/pitch/roll in degrees as binary float
#define OUTPUT__MODE_SENSORS_TEXT 3 // Outputs (calibrated) sensor values for all 9 axes as text
// Select your startup output mode here!
int output_mode = OUTPUT__MODE_ANGLES_TEXT;

// Select if serial continuous streaming output is enabled per default on startup.
#define OUTPUT__STARTUP_STREAM_ON true  // true or false

// If set true, an error message will be output if we fail to read sensor data.
// Message format: "!ERR: reading <sensor>", followed by "\r\n".
boolean output_errors = false;  // true or false

// Bluetooth
// You can set this to true, if you have a Rovering Networks Bluetooth Module attached.
// The connect/disconnect message prefix of the module has to be set to "#".
// (Refer to manual, it can be set like this: SO,#)
// When using this, streaming output will only be enabled as long as we're connected. That way
// receiver and sender are synchronzed easily just by connecting/disconnecting.
// It is not necessary to set this! It just makes life easier when writing code for
// the receiving side. The Processing test sketch also works without setting this.
// NOTE: When using this, OUTPUT__STARTUP_STREAM_ON has no effect!
#define OUTPUT__HAS_RN_BLUETOOTH false  // true or false


// SENSOR CALIBRATION
/*****************************************************************/
// How to calibrate? Read the tutorial at http://dev.qu.tu-berlin.de/projects/sf-razor-9dof-ahrs
// Put MIN/MAX and OFFSET readings for your board here!
// Accelerometer
// "accel x,y,z (min/max) = X_MIN/X_MAX  Y_MIN/Y_MAX  Z_MIN/Z_MAX"
#define ACCEL_X_MIN ((float) -275)
#define ACCEL_X_MAX ((float) 320)
#define ACCEL_Y_MIN ((float) -265)
#define ACCEL_Y_MAX ((float) 320)
#define ACCEL_Z_MIN ((float) -300)
#define ACCEL_Z_MAX ((float) 260)

// Magnetometer
// "magn x,y,z (min/max) = X_MIN/X_MAX  Y_MIN/Y_MAX  Z_MIN/Z_MAX"
#define MAGN_X_MIN ((float) -475)
#define MAGN_X_MAX ((float) 565)
#define MAGN_Y_MIN ((float) -288)
#define MAGN_Y_MAX ((float) 786)
#define MAGN_Z_MIN ((float) -511)
#define MAGN_Z_MAX ((float) 510)

// Gyroscope
// "gyro x,y,z (current/average) = .../OFFSET_X  .../OFFSET_Y  .../OFFSET_Z
#define GYRO_AVERAGE_OFFSET_X ((float) 7.13)
#define GYRO_AVERAGE_OFFSET_Y ((float) 25.78)
#define GYRO_AVERAGE_OFFSET_Z ((float) 19.54)

/*
// Calibration example:
 // "accel x,y,z (min/max) = -278.00/270.00  -254.00/284.00  -294.00/235.00"
 #define ACCEL_X_MIN ((float) -278)
 #define ACCEL_X_MAX ((float) 270)
 #define ACCEL_Y_MIN ((float) -254)
 #define ACCEL_Y_MAX ((float) 284)
 #define ACCEL_Z_MIN ((float) -294)
 #define ACCEL_Z_MAX ((float) 235)

 // "magn x,y,z (min/max) = -511.00/581.00  -516.00/568.00  -489.00/486.00"
 #define MAGN_X_MIN ((float) -511)
 #define MAGN_X_MAX ((float) 581)
 #define MAGN_Y_MIN ((float) -516)
 #define MAGN_Y_MAX ((float) 568)
 #define MAGN_Z_MIN ((float) -489)
 #define MAGN_Z_MAX ((float) 486)

 //"gyro x,y,z (current/average) = -32.00/-34.82  102.00/100.41  -16.00/-16.38"
 #define GYRO_AVERAGE_OFFSET_X ((float) -34.82)
 #define GYRO_AVERAGE_OFFSET_Y ((float) 100.41)
 #define GYRO_AVERAGE_OFFSET_Z ((float) -16.38)
 */


// DEBUG OPTIONS
/*****************************************************************/
// When set to true, gyro drift correction will not be applied
#define DEBUG__NO_DRIFT_CORRECTION false
// Print elapsed time after each I/O loop
#define DEBUG__PRINT_LOOP_TIME false


/*****************************************************************/
/****************** END OF USER SETUP AREA!  *********************/
/*****************************************************************/










// Check if hardware version code is defined
#ifndef HW__VERSION_CODE
// Generate compile error
#error YOU HAVE TO SELECT THE HARDWARE YOU ARE USING! See "HARDWARE OPTIONS" in "USER SETUP AREA" at top of Razor_AHRS.pde!
#endif

#include <Wire.h>

// Sensor calibration scale and offset values
#define ACCEL_X_OFFSET ((ACCEL_X_MIN + ACCEL_X_MAX) / 2.0f)
#define ACCEL_Y_OFFSET ((ACCEL_Y_MIN + ACCEL_Y_MAX) / 2.0f)
#define ACCEL_Z_OFFSET ((ACCEL_Z_MIN + ACCEL_Z_MAX) / 2.0f)
#define ACCEL_X_SCALE (GRAVITY / (ACCEL_X_MAX - ACCEL_X_OFFSET))
#define ACCEL_Y_SCALE (GRAVITY / (ACCEL_Y_MAX - ACCEL_Y_OFFSET))
#define ACCEL_Z_SCALE (GRAVITY / (ACCEL_Z_MAX - ACCEL_Z_OFFSET))

#define MAGN_X_OFFSET ((MAGN_X_MIN + MAGN_X_MAX) / 2.0f)
#define MAGN_Y_OFFSET ((MAGN_Y_MIN + MAGN_Y_MAX) / 2.0f)
#define MAGN_Z_OFFSET ((MAGN_Z_MIN + MAGN_Z_MAX) / 2.0f)
#define MAGN_X_SCALE (100.0f / (MAGN_X_MAX - MAGN_X_OFFSET))
#define MAGN_Y_SCALE (100.0f / (MAGN_Y_MAX - MAGN_Y_OFFSET))
#define MAGN_Z_SCALE (100.0f / (MAGN_Z_MAX - MAGN_Z_OFFSET))


// Gain for gyroscope (ITG-3200)
#define GYRO_GAIN 0.06957 // Same gain on all axes
#define GYRO_SCALED_RAD(x) (x * TO_RAD(GYRO_GAIN)) // Calculate the scaled gyro readings in radians per second

// DCM parameters
#define Kp_ROLLPITCH 0.02f
#define Ki_ROLLPITCH 0.00002f
#define Kp_YAW 1.2f
#define Ki_YAW 0.00002f

// Stuff
#define STATUS_LED_PIN 13  // Pin number of status LED
#define GRAVITY 256.0f // "1G reference" used for DCM filter and accelerometer calibration
#define TO_RAD(x) (x * 0.01745329252)  // *pi/180
#define TO_DEG(x) (x * 57.2957795131)  // *180/pi

// Sensor variables
float accel[3];  // Actually stores the NEGATED acceleration (equals gravity, if board not moving).
float accel_min[3];
float accel_max[3];

float magnetom[3];
float magnetom_min[3];
float magnetom_max[3];

float gyro[3];
float gyro_average[3];
int gyro_num_samples = 0;

// DCM variables
float MAG_Heading;
float Accel_Vector[3]= {
  0, 0, 0}; // Store the acceleration in a vector
float Gyro_Vector[3]= {
  0, 0, 0}; // Store the gyros turn rate in a vector
float Omega_Vector[3]= {
  0, 0, 0}; // Corrected Gyro_Vector data
float Omega_P[3]= {
  0, 0, 0}; // Omega Proportional correction
float Omega_I[3]= {
  0, 0, 0}; // Omega Integrator
float Omega[3]= {
  0, 0, 0};
float errorRollPitch[3] = {
  0, 0, 0};
float errorYaw[3] = {
  0, 0, 0};
float DCM_Matrix[3][3] = {
  {
    1, 0, 0  }
  , {
    0, 1, 0  }
  , {
    0, 0, 1  }
};
float Update_Matrix[3][3] = {
  {
    0, 1, 2  }
  , {
    3, 4, 5  }
  , {
    6, 7, 8  }
};
float Temporary_Matrix[3][3] = {
  {
    0, 0, 0  }
  , {
    0, 0, 0  }
  , {
    0, 0, 0  }
};

// Euler angles
float yaw;
float pitch;
float roll;

// DCM timing in the main loop
long timestamp;
long timestamp_old;
float G_Dt; // Integration time for DCM algorithm

// More output-state variables
boolean output_stream_on;
boolean output_single_on;
int curr_calibration_sensor = 0;
boolean reset_calibration_session_flag = true;
int num_accel_errors = 0;
int num_magn_errors = 0;
int num_gyro_errors = 0;

void read_sensors() {
  Read_Gyro(); // Read gyroscope
  Read_Accel(); // Read accelerometer
  Read_Magn(); // Read magnetometer
}

// Read every sensor and record a time stamp
// Init DCM with unfiltered orientation
// TODO re-init global vars?
void reset_sensor_fusion() {
  float temp1[3];
  float temp2[3];
  float xAxis[] = {
    1.0f, 0.0f, 0.0f  };

  read_sensors();
  timestamp = millis();

  // GET PITCH
  // Using y-z-plane-component/x-component of gravity vector
  pitch = -atan2(accel[0], sqrt(accel[1] * accel[1] + accel[2] * accel[2]));

  // GET ROLL
  // Compensate pitch of gravity vector
  Vector_Cross_Product(temp1, accel, xAxis);
  Vector_Cross_Product(temp2, xAxis, temp1);
  // Normally using x-z-plane-component/y-component of compensated gravity vector
  // roll = atan2(temp2[1], sqrt(temp2[0] * temp2[0] + temp2[2] * temp2[2]));
  // Since we compensated for pitch, x-z-plane-component equals z-component:
  roll = atan2(temp2[1], temp2[2]);

  // GET YAW
  Compass_Heading();
  yaw = MAG_Heading;

  // Init rotation matrix
  init_rotation_matrix(DCM_Matrix, yaw, pitch, roll);
}

// Apply calibration to raw sensor readings
void compensate_sensor_errors() {
  // Compensate accelerometer error
  accel[0] = (accel[0] - ACCEL_X_OFFSET) * ACCEL_X_SCALE;
  accel[1] = (accel[1] - ACCEL_Y_OFFSET) * ACCEL_Y_SCALE;
  accel[2] = (accel[2] - ACCEL_Z_OFFSET) * ACCEL_Z_SCALE;

  // Compensate magnetometer error
  magnetom[0] = (magnetom[0] - MAGN_X_OFFSET) * MAGN_X_SCALE;
  magnetom[1] = (magnetom[1] - MAGN_Y_OFFSET) * MAGN_Y_SCALE;
  magnetom[2] = (magnetom[2] - MAGN_Z_OFFSET) * MAGN_Z_SCALE;

  // Compensate gyroscope error
  gyro[0] -= GYRO_AVERAGE_OFFSET_X;
  gyro[1] -= GYRO_AVERAGE_OFFSET_Y;
  gyro[2] -= GYRO_AVERAGE_OFFSET_Z;
}

// Reset calibration session if reset_calibration_session_flag is set
void check_reset_calibration_session()
{
  // Raw sensor values have to be read already, but no error compensation applied

  // Reset this calibration session?
  if (!reset_calibration_session_flag) return;

  // Reset acc and mag calibration variables
  for (int i = 0; i < 3; i++) {
    accel_min[i] = accel_max[i] = accel[i];
    magnetom_min[i] = magnetom_max[i] = magnetom[i];
  }

  // Reset gyro calibration variables
  gyro_num_samples = 0;  // Reset gyro calibration averaging
  gyro_average[0] = gyro_average[1] = gyro_average[2] = 0.0f;

  reset_calibration_session_flag = false;
}

void turn_output_stream_on()
{
  output_stream_on = true;
  digitalWrite(STATUS_LED_PIN, HIGH);
}

void turn_output_stream_off()
{
  output_stream_on = false;
  digitalWrite(STATUS_LED_PIN, LOW);
}

// Blocks until another byte is available on serial port
char readChar()
{
  while (Serial.available() < 1) {
  } // Block
  return Serial.read();
}

void setup()
{
  // Init serial output
  Serial.begin(OUTPUT__BAUD_RATE);

  // Init status LED
  pinMode (STATUS_LED_PIN, OUTPUT);
  digitalWrite(STATUS_LED_PIN, LOW);

  // Init sensors
  delay(50);  // Give sensors enough time to start
  I2C_Init();
  Accel_Init();
  Magn_Init();
  Gyro_Init();

  // Read sensors, init DCM algorithm
  delay(20);  // Give sensors enough time to collect data
  reset_sensor_fusion();

  // Init output
#if (OUTPUT__HAS_RN_BLUETOOTH == true) || (OUTPUT__STARTUP_STREAM_ON == false)
  turn_output_stream_off();
#else
  turn_output_stream_on();
#endif
}

// Main loop
void loop()
{
  // Read incoming control messages
  if (Serial.available() >= 2)
  {
    if (Serial.read() == '#') // Start of new control message
    {
      int command = Serial.read(); // Commands
      if (command == 'f') // request one output _f_rame
        output_single_on = true;
      else if (command == 's') // _s_ynch request
      {
        // Read ID
        byte id[2];
        id[0] = readChar();
        id[1] = readChar();

        // Reply with synch message
        Serial.print("#SYNCH");
        Serial.write(id, 2);
        Serial.println();
      }
      else if (command == 'o') // Set _o_utput mode
      {
        char output_param = readChar();
        if (output_param == 'n')  // Calibrate _n_ext sensor
        {
          curr_calibration_sensor = (curr_calibration_sensor + 1) % 3;
          reset_calibration_session_flag = true;
        }
        else if (output_param == 't') // Output angles as _t_ext
          output_mode = OUTPUT__MODE_ANGLES_TEXT;
        else if (output_param == 'b') // Output angles in _b_inary form
          output_mode = OUTPUT__MODE_ANGLES_BINARY;
        else if (output_param == 'c') // Go to _c_alibration mode
        {
          output_mode = OUTPUT__MODE_CALIBRATE_SENSORS;
          reset_calibration_session_flag = true;
        }
        else if (output_param == 's') // Output _s_ensor values as text
          output_mode = OUTPUT__MODE_SENSORS_TEXT;
        else if (output_param == '0') // Disable continuous streaming output
        {
          turn_output_stream_off();
          reset_calibration_session_flag = true;
        }
        else if (output_param == '1') // Enable continuous streaming output
        {
          reset_calibration_session_flag = true;
          turn_output_stream_on();
        }
        else if (output_param == 'e') // _e_rror output settings
        {
          char error_param = readChar();
          if (error_param == '0') output_errors = false;
          else if (error_param == '1') output_errors = true;
          else if (error_param == 'c') // get error count
          {
            Serial.print("#AMG-ERR:");
            Serial.print(num_accel_errors);
            Serial.print(",");
            Serial.print(num_magn_errors);
            Serial.print(",");
            Serial.println(num_gyro_errors);
          }
        }
      }
#if OUTPUT__HAS_RN_BLUETOOTH == true
      // Read messages from bluetooth module
      // For this to work, the connect/disconnect message prefix of the module has to be set to "#".
      else if (command == 'C') // Bluetooth "#CONNECT" message (does the same as "#o1")
        turn_output_stream_on();
      else if (command == 'D') // Bluetooth "#DISCONNECT" message (does the same as "#o0")
        turn_output_stream_off();
#endif // OUTPUT__HAS_RN_BLUETOOTH == true
    }
    else
    {
    } // Skip character
  }

  // Time to read the sensors again?
  if((millis() - timestamp) >= OUTPUT__DATA_INTERVAL)
  {
    timestamp_old = timestamp;
    timestamp = millis();
    if (timestamp > timestamp_old)
      G_Dt = (float) (timestamp - timestamp_old) / 1000.0f; // Real time of loop run. We use this on the DCM algorithm (gyro integration time)
    else G_Dt = 0;

    // Update sensor readings
    read_sensors();

    if (output_mode == OUTPUT__MODE_CALIBRATE_SENSORS)  // We're in calibration mode
    {
      check_reset_calibration_session();  // Check if this session needs a reset
      if (output_stream_on || output_single_on) output_calibration(curr_calibration_sensor);
    }
    else if (output_mode == OUTPUT__MODE_SENSORS_TEXT)
    {
      // Apply sensor calibration
      compensate_sensor_errors();

      if (output_stream_on || output_single_on) output_sensors();
    }
    else
    {
      // Apply sensor calibration
      compensate_sensor_errors();

      // Run DCM algorithm
      Compass_Heading(); // Calculate magnetic heading
      Matrix_update();
      Normalize();
      Drift_correction();
      Euler_angles();

      if (output_stream_on || output_single_on) output_angles();
    }

    output_single_on = false;

#if DEBUG__PRINT_LOOP_TIME == true
    Serial.print("loop time (ms) = ");
    Serial.println(millis() - timestamp);
#endif
  }
#if DEBUG__PRINT_LOOP_TIME == true
  else
  {
    Serial.println("waiting...");
  }
#endif
}