Arduino Nano v3 + GY-521 (acc+gyro) --> Processing --> CSV, can't get it to work

dear all,

for school project have acceleration , filtered angle data acc+gyro (gy-521) sensor excel analyze them. use arduino nano v3 , macbook lion - osx 10.7.5.  today (for quick test) hoping let processing create simple csv y-accelerations in there, 1 on each row, can't work... processing sketch make csv file, it's it's empty , it's showing right values so:

-50,32
30,00
20
1,00

294,90
etc

it splits 201,00 somewhere in middle , adds empty line.

now question is: how possible writes empty file , filled file. , why filled jump @ random places next line? looks it's not in sync??! serial monitor of arduino environment gives perfect rows of values..

can me? much!

this processing sketch used:

code: [select]

import processing.serial.*;
serial myserial;
printwriter output;
//float accel_y;

void setup() {
  myserial = new serial( this, serial.list()[1], 19200 );
  output = createwriter( "documents/datalaumann5.txt" );
}

void draw() {
   if (myserial.available() > 0 ) {
        string accel_y = myserial.readstring();
        if ( accel_y != null ) {
             output.println(accel_y);
        }
   }
}

void keypressed() {
 output.flush();  // writes remaining data file
 output.close();  // finishes file
 exit();  // stops program
}

and arduino code (part of complete code):

code: [select]

 

  float accel_y;
 
}


void setup()
{     
  int error;
  uint8_t c;


  serial.begin(19200);
  /*
  serial.println(f("invensense mpu-6050"));
  serial.println(f("june 2012"));
  */
  // initialize 'wire' class i2c-bus.
  wire.begin();


  // default @ power-up:
  //    gyro @ 250 degrees second
  //    acceleration @ 2g
  //    clock source @ internal 8mhz
  //    device in sleep mode.
  //

  error = mpu6050_read (mpu6050_who_am_i, &c, 1);
  /*
  serial.print(f("who_am_i : "));
  serial.print(c,hex);
  serial.print(f(", error = "));
  serial.println(error,dec);
  */

  // according datasheet, 'sleep' bit
  // should read '1'. read '0'.
  // bit has cleared, since sensor
  // in sleep mode @ power-up. if the
  // bit reads '0'.
  error = mpu6050_read (mpu6050_pwr_mgmt_2, &c, 1);
  /*
  serial.print(f("pwr_mgmt_2 : "));
  serial.print(c,hex);
  serial.print(f(", error = "));
  serial.println(error,dec);
  */

  // clear 'sleep' bit start sensor.
  mpu6050_write_reg (mpu6050_pwr_mgmt_1, 0);
 
  //initialize angles
  calibrate_sensors(); 
  set_last_read_angle_data(millis(), 0, 0, 0, 0, 0, 0);
}


void loop()
{
  int error;
  double dt;
  accel_t_gyro_union accel_t_gyro;

  /*
  serial.println(f(""));
  serial.println(f("mpu-6050"));
  */
 
  // read raw values.
  error = read_gyro_accel_vals((uint8_t*) &accel_t_gyro);
 
  // time of reading rotation computations
  unsigned long t_now = millis();


  // convert gyro values degrees/sec
  float fs_sel = 131;
  /*
  float gyro_x = (accel_t_gyro.value.x_gyro - base_x_gyro)/fs_sel;
  float gyro_y = (accel_t_gyro.value.y_gyro - base_y_gyro)/fs_sel;
  float gyro_z = (accel_t_gyro.value.z_gyro - base_z_gyro)/fs_sel;
  */
  float gyro_x = (accel_t_gyro.value.x_gyro - base_x_gyro)/fs_sel;
  float gyro_y = (accel_t_gyro.value.y_gyro - base_y_gyro)/fs_sel;
  float gyro_z = (accel_t_gyro.value.z_gyro - base_z_gyro)/fs_sel;
 
 
  // raw acceleration values
  //float g_convert = 16384;
  float accel_x = accel_t_gyro.value.x_accel;
  float accel_y = accel_t_gyro.value.y_accel;
  float accel_z = accel_t_gyro.value.z_accel;
 
  // angle values accelerometer
  float radians_to_degrees = 180/3.14159;
//  float accel_vector_length = sqrt(pow(accel_x,2) + pow(accel_y,2) + pow(accel_z,2));
  float accel_angle_y = atan(-1*accel_x/sqrt(pow(accel_y,2) + pow(accel_z,2)))*radians_to_degrees;
  float accel_angle_x = atan(accel_y/sqrt(pow(accel_x,2) + pow(accel_z,2)))*radians_to_degrees;

  float accel_angle_z = 0;
 
  // compute (filtered) gyro angles
  float dt =(t_now - get_last_time())/1000.0;
  float gyro_angle_x = gyro_x*dt + get_last_x_angle();
  float gyro_angle_y = gyro_y*dt + get_last_y_angle();
  float gyro_angle_z = gyro_z*dt + get_last_z_angle();
 
  // compute drifting gyro angles
  float unfiltered_gyro_angle_x = gyro_x*dt + get_last_gyro_x_angle();
  float unfiltered_gyro_angle_y = gyro_y*dt + get_last_gyro_y_angle();
  float unfiltered_gyro_angle_z = gyro_z*dt + get_last_gyro_z_angle();
 
  // apply complementary filter figure out change in angle - choice of alpha is
  // estimated now.  alpha depends on sampling rate...
  float alpha = 0.96;
  float angle_x = alpha*gyro_angle_x + (1.0 - alpha)*accel_angle_x;
  float angle_y = alpha*gyro_angle_y + (1.0 - alpha)*accel_angle_y;
  float angle_z = gyro_angle_z;  //accelerometer doesn't give z-angle
 
  // update saved data latest values
  set_last_read_angle_data(t_now, angle_x, angle_y, angle_z, unfiltered_gyro_angle_x, unfiltered_gyro_angle_y, unfiltered_gyro_angle_z);
 
  // send data serial port
/*
  serial.print(f("del:"));              //delta t
  serial.print(dt, dec);
  serial.print(f("#acc:"));              //accelerometer angle
  serial.print(accel_angle_x, 2);
  serial.print(f(","));
  serial.print(accel_angle_y, 2);
  serial.print(f(","));
  serial.print(accel_angle_z, 2);
  serial.print(f("#gyr:"));
  serial.print(unfiltered_gyro_angle_x, 2);        //gyroscope angle
  serial.print(f(","));
  serial.print(unfiltered_gyro_angle_y, 2);
  serial.print(f(","));
  serial.print(unfiltered_gyro_angle_z, 2);
  serial.print(f("#fil:"));             //filtered angle
  serial.print(angle_x, 2);
  serial.print(f(","));
  serial.print(angle_y, 2);
  serial.print(f(","));
  serial.print(angle_z, 2);
  serial.println(f(""));
*/
 
  serial.println(accel_y);

  // delay don't swamp serial port
  //delay(200);
}


code: [select]

         string accel_y = myserial.readstring();
what, exactly, defines string? makes readstring() stop reading?

you should have serialevent() function, instead of doing serial reading in draw().
you should have myserial.bufferuntil() statement in setup(), define when trigger serialevent() method, , should use readbytesuntil() in serialevent().

Arduino Forum > Using Arduino > Interfacing w/ Software on the Computer > Arduino Nano v3 + GY-521 (acc+gyro) --> Processing --> CSV, can't get it to work

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