How do i make MATLAB remember moments in the code?

Hi!

This is my GUI code:

The problem i got is when im press pushbutton1_Callback the function is running this:

a=arduino('COM4');
a.pinMode(9, 'OUTPUT');
a.digitalWrite(9, 1);
msgbox('ON');

a=arduini('COM4') means that the program connecting to the Arduino UNO card. a.pinMode(9, 'OUTPUT') means that the program declare that pin 9 is an output for current. a.digitalWrite(9, 1) means that the LED lamp is ON. msgbox('ON') means that after the program has turn on the LED lamp, a message bos will show up.

My problem is when the message box shows up, the LED lamp turn OFF. My program cannot remember the moments it has read.

If i place this code

a=arduino('COM4');
a.pinMode(9, 'OUTPUT');

in the first function above of the code below and remove the same code in the push button functions

function pushbutton2_Callback(hObject, eventdata, handles)
a.digitalWrite(9, 0);
msgbox('OFF');

i got error if a press any function push button. The error is "I don't know what a or a.digitalWrite are??". Just because the program don't remember that it has run this code before

a=arduino('COM4');
a.pinMode(9, 'OUTPUT');

This is my whole code:

function varargout = First(varargin)
% FIRST MATLAB code for First.fig
%      FIRST, by itself, creates a new FIRST or raises the existing
%      singleton*.
%
%      H = FIRST returns the handle to a new FIRST or the handle to
%      the existing singleton*.
%
%      FIRST('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in FIRST.M with the given input arguments.
%
%      FIRST('Property','Value',...) creates a new FIRST or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before First_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to First_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help First

% Last Modified by GUIDE v2.5 19-Jul-2014 22:43:46

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @First_OpeningFcn, ...
                   'gui_OutputFcn',  @First_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT

% --- Executes just before First is made visible.
function First_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 First (see VARARGIN)

% Choose default command line output for First
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes First wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% --- Outputs from this function are returned to the command line.
function varargout = First_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
a=arduino('COM4');
a.pinMode(9, 'OUTPUT');
a.digitalWrite(9, 1);
 msgbox('ON');

% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
a=arduino('COM4');
a.pinMode(9, 'OUTPUT');
a.digitalWrite(9, 0);
msgbox('OFF');

% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

Answer 1

[Image Analyst]

You probably have the LED reversed. Try turning it around. Have the + side go into pin 9, the - side go into the breadboard and a resistor going from the breadboard to ground.