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