MATLAB App Designer: Error while evaluating TimerFcn for timer 'timer-5' Undefined function 'write' for input arguments of type 'string'.

Hi, i am trying to use a timer to send data through serial port to arduino at a fixed rate. However, the error is like this: Error while evaluating TimerFcn for timer 'timer-5' Undefined function 'write' for input arguments of type 'string'.

This is the code related to the timer:

function startupFcn(app)

app.mytimer = timer('Period',0.2,'ExecutionMode','fixedRate');

app.mytimer.TimerFcn = @app.TimerCallback; % Your Timer Callback

end

This is the timer call back function:

function timertt = TimerCallback(app, ~, ~)

% Timer callback

app.sendData(app.motor_qc);

end

function sendData(app,tosend)

tosend = string(tosend);

write(app.arduino,tosend,"string");

end

I'm sure "write" for "string" can work ouside the timer. I used a button to trigger the sendData function, and it works well. But if it is inside the timer, it doesn't work. Is there any solution for this?

Answer 1

[Shreyansh Mehra]

Hello,

Please refer to the following post, which presents solutions that are possibly relevant to this error message:

https://www.mathworks.com/matlabcentral/answers/96005-why-do-i-get-the-error-undefined-function-or-variable