I am trying to connect an Arduino to Matlab and "fopen" or "BytesAvailable" give me errors.

What needs to be changed in order for this code to run correctly? The fopen error says it needs a valid file, and the "BytesAvailable" error gives: "Unrecognized method, property, or field 'BytesAvailable' for class 'internal.Serialport'."

Matlab Code:

function OpenSerialButtonPushed(app, event)
             
                app.ArduinoUno= serialport(strcat('COM',num2str(app.COMPortDropDown.Value)), 9600);
              
                fopen(app.ArduinoUno);
                pause(0.01);

while app.ArduinoUno.BytesAvailable > 0 || counter < 5
        inByte = fscanf(app.ArduinoUno, '%c', 1);
        counter = counter + 1;

        if counter == 5
           errordlg('Connect arduino to the computer or type in correct COM port')
           set(app.ConnectionStatusLabel,'String', 'Connection Failed');
                break
        end
              
                 if inByte == 'c' 
                set(app.ConnectionStatusLabel.Text, 'String', 'Connection Successful');
                 end
              
                 
                 
                
                
end
              
        end

Answer 1

[Prateek]

Hi Jake,

A valid “COM” port is required by “fopen”. Please debug the code to ensure that an available “COM” port is being passed to “fopen”.

Also, in MATLAB R2022a, the “serialport” objects have a property “NumBytesAvailable” to ascertain amount of incoming data available to be read. Thus, changing the “BytesAvailable” to “NumBytesAvailable” may resolve the error.

Hope this helps. For better assistance, I request you to post the app designer file and complete code.

Regards,

Prateek