Matlab Mobile - Extracting my sensor data isnt working properly.

Hello all,

i am working with matlab mobile and i am facing a rather annoying problem. I dont even know if it is caused by Matlab Mobile/Matlab/Android or my Smartphone. I work with Matlab R2016a.

After i have created a successful connection between the smartphone and matlab and logged some data, i want to extract it via [Accel, t_Accel] = accellog(m). But the results i get seem to be corrupt/broken. The timevector isnt contiguous and i receive too few data. If i shake my phone for like 15 seconds and the contiguous party of timevec imply a frequency of ~12 Hz my Datamatrix is only 70x3 and not ~180x3 as i would expect.

Does anyone of you know where my problem occurs from? I tested 2 different smartphones and controlling matlab mobile on the smartphone and in matlab with console commands (m.Logging =1 ; m.Logging =0;) and i still get similar problems.

I hope someone has a smart idea.

Greetings

Answer 1

[Daniel Hauch]

I fixed the problem!

If anyone is interested, i will write a quick report.

Making timevector contiguous: delete old mobiledev and create a new one. I dont know why this problem occurs, but this is a simple fix.

Receive logged data completly: Matlab Mobile needs quite some time to postprocess the logged data. Therefore you have to wait some time until the log-functions return vectors with the appropiate length. I automated this process with the code showing below:

t_Accel_old = 0;

while true
    %get data from mobiledev and save in var
    [Accel, t_Accel] = accellog(m);

      if length(t_Accel_old)==length(t_Accel)
          break;
      end

      t_Accel_old = t_Accel;

      pause(2);
  end

I hope my explanation is helpful and saves someone some time.

Greetings

[Bushra]

clc;

clear all;

clear a;

a = arduino('COM5', 'Uno');

fs = 100; % Sample Rate in Hz

imu = mpu6050(a,'SampleRate',fs,'OutputFormat','matrix');

ts = tic;

stopTimer = 50;

magReadings=[];

while(toc(ts) < stopTimer)

[accel,gyro] = read(imu);

end

GyroscopeNoiseMPU9250 = 3.0462e-06; % GyroscopeNoise (variance value) in units of rad/s

AccelerometerNoiseMPU9250 = 0.0061; % AccelerometerNoise (variance value) in units of m/s^2

viewer = HelperOrientationViewer('Title',{'AHRS Filter'});

FUSE = ahrsfilter('SampleRate',imu.SampleRate, 'GyroscopeNoise',GyroscopeNoiseMPU9250,'AccelerometerNoise',AccelerometerNoiseMPU9250);

stopTimer = 100;

ts = tic;

while(toc(ts) < stopTimer)

[accel,gyro] = read(imu);

% Align coordinates in accordance with NED convention

accel = [-accel(:,2), -accel(:,1), accel(:,3)];

gyro = [gyro(:,2), gyro(:,1), -gyro(:,3)];

rotators = FUSE(accel,gyro);

for j = numel(rotators)

viewer(rotators(j));

end

end

I am reading data from mpu6050 using arduino in MATLAB. I am receiving this error

Error using mpu6050_Arduino12

Command logs are not supported for sensors. Create the hardware Object with property 'TraceOn' disabled.

Can you help me with that?