hi, i want to do real time plot via gui. I'm getting the data from Arduino, but I can't plot, where am I missing my code is as follows. -Best regards.

% --- Executes on button press in Connect.

function Connect_Callback(hObject, eventdata, handles)

% hObject handle to Connect (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user ggg (see GUIDATA)

handles.s=serial('COM3','BaudRate',9600);

handles.s.BytesAvailableFcn = {@ReadDataOverSerial,handles};

handles.s.BytesAvailableFcnCount=12;

handles.s.BytesAvailableFcnMod='byte';

fopen(handles.s);

guidata(hObject, handles);

function ReadDataOverSerial(hObject, eventdata, handles)

global a b ;

bytes=fread(handles.s,[1,handles.s.BytesAvailable]);

set(handles.datavalues,'String',char(bytes));

timer = bytes(end-5:end); %creating new speacial array

response = bytes(1:5); %creating new speacial array

timer = str2double(timer);

response = str2double(response);

a = [a timer];

b = [b response];

plot(handles.axes1,a,b);

Answer 1

[Chetan]

Hello @efe zorlukol,

I understand you're facing issues with real-time plotting in a MATLAB GUI using data from an Arduino. Let's address the key points to resolve this:

1. Initialization: Confirm `a` and `b` are initialized as empty before data collection starts.
2. Data Handling: Ensure `timer` and `response` are converted to numbers without errors.
3. Plotting: After updating `a` and `b`, use `plot(handles.axes1, a, b);` followed by `drawnow;` to refresh the plot.

Here's a updated version of your `ReadDataOverSerial` function:

function ReadDataOverSerial(hObject, ~, handles)
global a b;
a = []; b = []; % Initialize if necessary

if handles.s.BytesAvailable > 0
    bytes = fread(handles.s, handles.s.BytesAvailable);
    timer = str2double(char(bytes(end-5:end)));
    response = str2double(char(bytes(1:5)));
    
    if ~isnan(timer) && ~isnan(response)
        a = [a timer]; b = [b response];
        plot(handles.axes1, a, b); drawnow;
    end
end
end

Refer to the following MathWorks Documentation:

• https://www.mathworks.com/help/matlab/serial-port-devices.html
• https://www.mathworks.com/help/matlab/ref/drawnow.html

Thanks

Chetan Verma