How can I read the actual analog read?

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

[SyukriY]

Because I want to calculate the temperature using the LM35 sensor. So, the calculation is like this.

temp = (5.0 * analogRead(A0) * 100.0) / 1024;

because the value from the analog read is like this somehow.

169 296 300 299 302

Answer 1

[SyukriY]

You can actually read the analog value using readVoltage.

You just need to make some calculation.

analog = readVoltage * (1023 / 5);

Answer 2

[Walter Roberson]

max('ardu1') means to apply max() to the vector that is the character string 'a', 'r', 'd', 'u', '1'.

There is no MATLAB operator for finding the max() of a .mat file.

Consider max(H)

[SyukriY]

Oooh... Now I know about the max and min value. But how can I read the actual analog read?

[Walter Roberson]

You stored them in H

[SyukriY]

The data is stored in H. But the value is from 'readVoltage'. In the arduino, I get the analog value such as this [169 296 300 299 302]. But by reading the readVoltage the value is not the same. What should I do to get or (maybe convert the readVoltage value) to become the analog value.

[SyukriY]

Because I noticed the value is not the same and with that, I cannot proceed with my thermistor calculation to get temperature value.