Calculate RPS by Matlab GUI and Arduino. I can't put the timing correctly. how can I do it?

% --- Executes on button press in togglebutton3.
function togglebutton3_Callback(hObject, eventdata, handles)
% hObject    handle to togglebutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hint: get(hObject,'Value') returns toggle state of togglebutton3
global a;
tic
c = 0; %initial amount of c as 0
while get(hObject,'Value')
    ti=toc
val = readDigitalPin(a, 'D6');       %reading the analog value from the sensor
if val == 1                           %if it gets 1
    c=c+1 %c increments by 1
    c=c/ti %dividing number of pulses by seconds
    set(handles.edit2,'String', c) %displays rev/sec
elseif val==0
    set(handles.edit2,'String', 0) %displays rev/sec
    
end
    pause(0.2);

end

Answer 1

[BhaTTa]

Hey @Omar Hameed, Let's take a look at your setup for calculating RPS using MATLAB GUI and Arduino. It seems like there are a couple of tweaks we can make to get the timing right and ensure you're calculating revolutions per second accurately.

Here's a refined version of your code with some explanations:

% --- Executes on button press in togglebutton3.
function togglebutton3_Callback(hObject, eventdata, handles)
    global a;  % Make sure your Arduino object is accessible
    c = 0;     % Start with zero pulses counted
    prevTime = tic;  % Start the timer to measure time intervals

    while get(hObject, 'Value')  % Keep running as long as the button is toggled on
        % Read the digital signal from the Arduino
        val = readDigitalPin(a, 'D6');

        % Check if a pulse is detected
        if val == 1
            c = c + 1;  % Increment the pulse count

            % Calculate the elapsed time since the last reset
            elapsedTime = toc(prevTime);

            % Compute revolutions per second
            if elapsedTime > 0
                rps = c / elapsedTime;  % Calculate RPS
                set(handles.edit2, 'String', rps);  % Update the GUI with the RPS value
            end

            % Reset for the next measurement
            c = 0;
            prevTime = tic;  % Restart the timer
        end

        % Small pause to prevent rapid fluctuations and handle debounce
        pause(0.2);
    end
end

To accurately calculate revolutions per second (RPS) using MATLAB GUI and Arduino, you need to ensure that the timing is correctly managed. The current implementation has some issues: the value of c is being divided by ti inside the loop, which may not give you the correct RPS, and the timing (tic and toc) is not being reset correctly for each revolution.