how can I automatically connect Arduino to the correct port?

Hi,

I am trying to connect an Arduino to Matlab, and then write to it. I can do this without any problems if I know the correct port in advance. However, this device will have to work on many different PC's (and in the future, cross platform) so I need to read the ports and see if an Arduino is connected.

The problem is, some computers have other devices connected to the serial port, and I have no way of knowing if the Arduino is the serial port that my code (below) found. Using get('serial port object') does not give me any special properties by which I can identify an Arduino is connected.

Yes, I know its easy to look at the device manager on Windows and see which port the Arduino is connected to, but I am trying to avoid this step for my users...

Thanks

Roee

function msp= startArduino()
% find out which port Arduino is connected to:
portNum=1;
wrongPort=1;
while wrongPort
    msp = serial(['COM' num2str(portNum)]);
    try 
        set(msp, 'BaudRate', 9600);
        set(msp, 'OutputBufferSize', 7);
        fopen(msp); %go to catch if can't open
        wrongPort=0; % found the right one - exit while loop!
    catch 
        delete(msp);
        clear msp
        instrreset % close any wrongly opened connection
        wrongPort =1 ; % keep trying... 
    end
    portNum=portNum+1;

      if portNum==16
          error('Arduino is not connected')
      end
  end

end

[Ryan G]

You could program the arduino to periodically send a message/flag letting you know what it is. There is likely a better way, might be a better suited question for arduino forums as it's more generic to arduino.

[Adithya Vivek]

Did you get any answer? I'm having exactly the same issue. I'm unable to make any other codes I have seen of similar functionality to work and I understand them regardless.

Answer 1

[Dennis Kachila]

Hello I was faced with the same exact challenge you describe and searched online for avaible solution unfortunately I didn't find the one I need .

So I decided to breakdown the problem into parts as shown in the folling steps below:

step 1: Listing all avalable ports

ports = serialportlist("all");

step 2 loop through the ports while Trying to connect to Arduino on current port

for i = 1:length(ports)
    try
        arduinoObject = arduino(ports(i), 'Uno');
    catch ME

    end
end

step 3 To verify if the board is connect to arduino use one of the arduinoObject property to check if it matches

if strcmp(arduinoObject.Board, "Uno")  % You may usem arduinoObject.Board, or arduinoObject.Port, in my case i used 'Board'
    % if success return the arduinoObject so that you may use it later for
    % reading voltages or writing
    
end

Here is the COMPLETE sample code

  % Get list of available COM ports
    ports = serialportlist("all");
    
    % Loop through all available ports and try to connect to an Arduino
    for i = 1:length(ports)
        try
            % Try to connect to Arduino on current port
            arduinoObject = arduino(ports(i), 'Uno'); % if The Arduino board is Nano use 'Nano3' and so on
            
            % Check if Arduino is an Uno
          if strcmp(arduinoObject.Board, "Uno")
                % Store the Arduino object in the app.Arduino property to
                ArduinoObj = arduinoObject;
               
                % Display message for successful connection 
                disp(["Arduino connected to " + ports(i)]) ;
                
                % Exit the loop
                break;
            else
                % If the port is not connected to an Uno, close the Arduino object
                clear arduinoObject;
            end
        catch
            % If there is an error connecting to the Arduino, try the next port
            disp(["Arduino port " + ports(i) + " incorrect trying the next com"]);
            clear arduinoObject;
            continue;
       end
    end 
 
 % If no Arduino was found, display error message
 if isempty(arduinoObj)
        disp("No Arduino found");
 end
   

Hoping it helps.