% --- Executes on button press in read_signal.
function read_signal_Callback(hObject, eventdata, handles)
% hObject    handle to read_signal (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
cla reset

fs=1;

% ROUTINE FOR REAL TIME READING
% create arduino object
delete(instrfind)
a = serial('COM5');                            %define serial port
a.BaudRate=115200;                               %define baud rate

%open serial port
fopen(a);

k = 0;  %index
v = 0;  %voltage
t = 0;  %time

axes(handles.axes1)
plotGraph=plot(t,v);
xlabel ('Time (s)'), ylabel('Voltage');
axis([0 30 0 5]);

scrollWidth=30; %window width
delay=1/fs;  %distance between two samples

tic % Start timer
while(1)
    threshold_im=str2double(get(handles.threshold,'String'));
    time_im= str2double(get(handles.time,'String'));

    k=k+1;
    v_read=fscanf(a,'%s'); %read arduino

    t(k) = toc;    %Extract Elapsed Time
    v(k)=str2double(v_read);
    th_y(k)=threshold_im;
    date=clock;

    A=[date v(k) time_im threshold_im];%A is vector with date (minute resolution), voltage amplitude (V), time over threshold imposed and threshold

    % Writing the signal value with data attached in a file
    fileID=fopen('pastsignal.txt','a');
    fprintf(fileID,'n%.0f %.0f %.0f %.0f %.0f %.0f %.2f %.2f %.2frn', A(1),A(2),A(3),A(4),A(5),A(6),A(7),A(8),A(9));
    fclose(fileID);

    if(scrollWidth > 0)
        plotGraph=plot(t(t > t(k)-scrollWidth),v(t > t(k)-scrollWidth),'b'); hold on
        plot(t(t > t(k)-scrollWidth),th_y(t > t(k)-scrollWidth),'r')
        axis([t(k)-scrollWidth t(k) 0 5]);
    else
        plotGraph=plot(t,v,'b'); hold on
        plot(t,th_y,'r')
        axis([0 t(k) 0 5]);
    end
    %Allow MATLAB to Update Plot
    pause(delay);

end
% close the serial port!
     fclose(a);