Matlab - checks on imported data

[bakes1]

A bit of background~
I'm using a wii mote to collect accelerometer data, and have the data exported to an excel document.

This data is then imported into MATLAB using :
a = xlsread(fileName); %reads in file name
x = a(:, xColNum); %time
y1 = a(:, y1ColNum); %accel value x
y2 = a(:, y2ColNum); %accel value y
y3 = a(:, y3ColNum); %accel value z

what i'd like to do next is then set a threshold check so that if any of the values within each of the sets is greater than a decided value a trigger can be set.

I'm not sure how to run the initial check on the y1, y2 ,y3 values. My first thoughts are to run a for loop on the sets and then have if statements that execute when the given values are reached. My only problem is I'm not quite sure how to code this within the m file. Also should it be part of a separate function of just below the above code.

 

[Mark44]

You could have three flag variables, one for each column, that are initialized to 0 and are set if you find a value that is above the threshold in a particular column. If you're interested only if any value in any of the three columns is above the threshold, you can probably get by with just one flag variable.

flag1 = 0
flag2 = 0
flag3 = 0
Threshold = 10000 % or whatever

for i=1:N
  if y1(i) >= Threshold
    flag1 = 1
  end
end

 

[oswaler]

As a scientist, it is important to ensure the accuracy and validity of data collected and imported into MATLAB. One way to do this is by setting threshold checks, as mentioned in the provided content. This can help identify any outliers or abnormal values that may affect the overall analysis and conclusions drawn from the data.

In order to implement this, you could use a for loop and if statements as mentioned. It is best to include this code below the initial data import and manipulation, as it is a continuation of the data processing. However, it is important to also consider creating a separate function for this threshold check, as it can make the code more organized and easier to debug if any issues arise.

In terms of the coding itself, you could use logical operators such as "greater than" and "less than" to check if the values exceed the decided threshold. It may also be helpful to use a counter to keep track of the number of times the threshold is exceeded, and potentially include a warning or error message if it exceeds a certain number of times.

Additionally, it may be beneficial to plot the data and visually inspect it for any anomalies or patterns that may require further investigation. This can also help in determining the appropriate threshold value to use.

Overall, incorporating threshold checks in your MATLAB code is a good practice to ensure the reliability of your data and the accuracy of your analysis.