Undefined function error for readDistance function within GUI editor

Question

Marisa Assink 2023-10-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2030694-undefined-function-error-for-readdistance-function-within-gui-editor

回答： Marisa Assink 2023-10-21

I am using the function readDistance() with an Arduino and HC - SR04 ultrasonic sensor. I have tested it in the command line to ensure my equipment is working and successfully received the distance value. However, for my assignment, I need to create a GUI and get the data there. When I try to use it in the GUI editor, I get the following error: 'Undefined function 'readDistance' for input arguments of type 'double'. '

I am using it in this context:

        function CollectDataButtonPushed(app, event)
            data = zeros(1e4,1);
            t = zeros(1e4,1);
            i = 1;
            tic
            while toc < 10
                value = readDistance(app.us);
                data(i) = value;
                data(i) = data(i) * 100;    %convert from m to cm
                t(i) = toc;
                i = i + 1;
            end
            plot(app.UIAxes, data);
            %writetable(T,filename);
        end

I have declared and set up my Arduino and sensor like this:

    properties (Access = private)
        a % arduino
        us % ultrasound sensor
    end
    app.a = arduino('COM4', 'Uno', "Libraries", "Ultrasonic");
    app.us = app.a.ultrasonic('D7','D6');

I have also tried to use the function like the following, but I get an error that says 'Dot indexing is not supported for variables of this type.'

value = app.us.readDistance();

I have tried searching for this error, but all I can find are the pages on how to use the readDistance() function which don't offer specific help.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Marisa Assink 2023-10-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2030694-undefined-function-error-for-readdistance-function-within-gui-editor#answer_1338231

I was able to figure it out, it was a problem with my ISP (Xfinity). Works fine with no edits on different networks, or at home with the wifi off on my laptop.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Yash Sharma 2023-10-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2030694-undefined-function-error-for-readdistance-function-within-gui-editor#answer_1335419

在 MATLAB Online 中打开

Hi Marisa,

I understand that you are unable to use the function “readDistance()” with an Arduino and HC - SR04 ultrasonic sensor, I believe that you have defined the ultrasonic object in an incorrect way, to define it correctly you should use the following syntax:

app.us = ultrasonic(app.a, ‘D7’, ‘D6’ ).