Display continuous alert in GUI from serial data

Hello guys. I need help to continuously display alert in edit box based on digital serial data recieved, 0 or 1. For now, i only get to read from serial port once so the alerts wont change based on the serial data.

Can anyone show me the coding to add below to continuously display alert based on serial data i recieve from arduino? How should i use loop in this?

Thankyou in advance :)

% --- Executes just before level_simulation is made visible.
function level_simulation_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to level_simulation (see VARARGIN)

% Choose default command line output for level_simulation
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
delete(instrfind({'PORT'},{'COM3'}));
clear a;
clc;
global a;
a = arduino('com3','uno');

x = 0;
global a;
reading = readDigitalPin(a,'D3');
set(handles.edit1,'String',num2str(reading)); % edit1 is the tag of edit box used to display the temperature
if reading == 1
  set(handles.edit2,'String','FIRST ALERT'); % edit2 is the tag of edit box used to display the alert
  set(handles.edit3,'String','');
elseif reading == 0
  set(handles.edit3,'String','SECOND ALERT');
  set(handles.edit2,'String','');
else
  set(handles.edit2,'String','');
  set(handles.edit3,'String','');
end

[Walter Roberson]

global a;
while true
    reading = readDigitalPin(a,'D3');
    set(handles.edit1,'String',num2str(reading)); % edit1 is the tag of edit box used to display the temperature
    if reading == 1
      set(handles.edit2,'String','FIRST ALERT'); % edit2 is the tag of edit box used to display the alert
      set(handles.edit3,'String','');
    elseif reading == 0
      set(handles.edit3,'String','SECOND ALERT');
      set(handles.edit2,'String','');
    else
      set(handles.edit2,'String','');
      set(handles.edit3,'String','');
    end
    pause(0.1);  %or as appropriate
end

[Iemad Sofi]

i tried your code. but its busy (loading) forever and my GUI dosnt appear. Im sorry but do you have another way of doing this?

[Iemad Sofi]

i tried using for and it worked. Just had to put long duration (3600 or more for longer duration)

global a k;

for k=1:1:3600
    reading = readDigitalPin(a,'D3');
    set(handles.edit1,'String',num2str(reading)); % edit1 is the tag of edit box used to display the temperature
    if reading == 1
      set(handles.edit2,'String','FIRST ALERT'); % edit2 is the tag of edit box used to display the alert
      set(handles.edit3,'String','');
    elseif reading == 0
      set(handles.edit3,'String','SECOND ALERT');
      set(handles.edit2,'String','');
    else
      set(handles.edit2,'String','');
      set(handles.edit3,'String','');
    end
    pause(1);  %or as appropriate
end

[Walter Roberson]

Don't put the loop in the open fcn callback.

Answer 1

[Guillermo Rubio Gomez]

The problem is that you are doing what you need just once, when the GUI starts, since your code is placed only in the OpeningFcn

You can not use a

while true
  
end

loop to place your code in since it will keep that code executing perpetually, preventing GUIDE to refresh.

I think that you need to declare a timer object in your OpeningFcn, with a period of 1s for example, or a rate that allows you to continuosly read the data while allowing GUI to refresh. Then you have to link a function with the timer, the function is responsible for receive data from the serial port and display the alert in GUI. The code could be like this:

% --- Executes just before level_simulation is made visible.
function level_simulation_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to level_simulation (see VARARGIN)
% Choose default command line output for level_simulation
handles.output = hObject;

delete(instrfind({'PORT'},{'COM3'}));

clear a;
clc;
global a;
a = arduino('com3','uno');
x = 0;
global a;

%% here you create your timer object, a period of 1s could work for what you need
handles.timer1 = timer(...
    'ExecutionMode', 'fixedRate', ...       % Continuous execution
    'Period', 1, ...                       % 1s Period
    'TimerFcn', {@update_display,hObject}); % Function executed in each timer execution

%% Lets start the timer, so it will call the timerFcn every period time
start(handles.timer1)

% Now you have to update the handles structure after defining the timer
guidata(hObject, handles);


reading = readDigitalPin(a,'D3');
set(handles.edit1,'String',num2str(reading)); % edit1 is the tag of edit box used to display the temperature
if reading == 1
  set(handles.edit2,'String','FIRST ALERT'); % edit2 is the tag of edit box used to display the alert
  set(handles.edit3,'String','');
elseif reading == 0
  set(handles.edit3,'String','SECOND ALERT');
  set(handles.edit2,'String','');
else
  set(handles.edit2,'String','');
  set(handles.edit3,'String','');
end


% Then, in the callback section, you add the function linked to the timer object:
function update_display(hObject,eventdata,data)
% Function that executes on each timer period
% Obtain handles data strcuture
handles = guidata(data);

% Now you add the code you need to execute perdiodically
reading = readDigitalPin(a,'D3');
set(handles.edit1,'String',num2str(reading)); % edit1 is the tag of edit box used to display the temperature
if reading == 1
  set(handles.edit2,'String','FIRST ALERT'); % edit2 is the tag of edit box used to display the alert
  set(handles.edit3,'String','');
elseif reading == 0
  set(handles.edit3,'String','SECOND ALERT');
  set(handles.edit2,'String','');
else
  set(handles.edit2,'String','');
  set(handles.edit3,'String','');
end

% finally update the handles structure
guidata(data,handles);

I think that should work.

Additionally, I would add the "a" variable to the handles structure, instead of declaring it as a global variable. Also, you can use the stop a start functions of the timer for example to use a button to start and stop the data refreshing.

[Iemad Sofi]

thankyou so much. i appreciate your help. ill try it