Exporting .txt file with timestamp for live data.

Hello,

I'm currently measuring roll, yaw, and pitch on my imu sensor in live time. I'm exporting a file as a 3 column txt file for x,y, and z. I want to add a time stamp for an additional column, for each set of data that I get. How would I go about this? Here's a snippet of my current code. Thanks in advanced.

%%
interv=50;
init_time=1;
x=0;
y=0;
z=0;
while(init_time<interv) 
  b=ez.CurrentData.YawPitchRoll.X;
  c=ez.CurrentData.YawPitchRoll.Y;
  d=ez.CurrentData.YawPitchRoll.Z;
  x=[x,b]; %roll
  y=[y,c]; %pitch 
  z =[z,d]; %yaw  
  plot(x, 'r')
  plot(y,'k')
  plot(z,'b')
  title('IMU Orientation Test')
  xlabel('Time (s)')
  ylabel('\theta')
  legend('Roll','Pitch','Yaw')
  ylim([-200 200])
  xlim([0 interv])
  grid on
  hold on  
  drawnow
  init_time=init_time+1;
end
dlmwrite('VectorNav.txt',[x' y' z'],'newline','pc')

[dpb]

For what time--each sample or for the dataset as a whole? Is this just a polling operation or are is the device sampling at a known rate and you're just returning those values?

[John Andrew]

sorry for the delayed response, but i want to add a time stamp next to each data point during live time testing. For ex; if i have 200 data points, then i would like to have 200 separate time stamps for each data point in my txt file in a 4th column

[Brendan Hamm]

If you mean the current timestamp at run time:

d = datetime('now')

You may wish to tchange the display format if your code is running fairly quickly:

d = datetime('now','Format','dd-MMM-yyyy HH:mm:ss.SS')

[John Andrew]

Thank you kind sir :D