Undefined function error for readDistance function within GUI editor
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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.
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Hornett
2024-9-17
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’ ).
In this code snippet,‘app.a’represents the arduino object,'D7'is the trigger pin, and'D6'is the echo pin.
Please find the documentation of the “ultrasonic” function below:
Hope this helps!
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