MATLAB: How to read the actual analog read

Question

Hi, MathWorks communities.

I have a question regarding the "readVoltage(a, ' ') command. When I run my code it shows a voltage data. But when I try to find the maximum or minimum value it shows something else. Can anyone tell me why it happens like that?

clear all;
a = arduino();
      for r = 1:10
          H(1,r) = readVoltage(a , 'A0')
          pause(1);
      end
  ts = timeseries(H(1,:),1:length(H)); %(data)(time)
  save('ardu1','ts','-v7.3')

This is the answer from command window.

H =
    Columns 1 through 6
      0.2639    0.2639    0.2639    0.2639    0.2639    0.2639
    Columns 7 through 10
      0.2639    0.2639    0.2688    0.2639
>> maximum = max('ardu1')
maximum =
     117
>> minimum = min('ardu1')
minimum =
      49

Answer 1

You can actually read the analog value using readVoltage.

You just need to make some calculation.

analog = readVoltage * (1023 / 5);