Displaying Timer Function in Graph

Hi,

I have created a timer function, which after every second displays EEG data coming through.

I want this to be displayed in a graph not in the command window. How is this possible? Currently it displays the text in the command window

The code is attached

[Geoff Hayes]

sufyan - your code is simply

plot(handles.graph, handles.data, handles.timer) 
t = timer('TimerFcn',{@timerCallback,handles},...
                   'Period',2,'ExecutionMode','fixedRate');
start(t)
function timerCallback(myTimerObj, ~, handles)
size(handles.data)
handles.timer = t

and so it is unclear how it is all related. Where is the EEG data coming from? Is it the handles.data? Note that you don't want to be passing in handles as an input to the timer callback since this is a copy of the handles structure and so won't have any of its fields updated. Instead you will want to pass in the handle to the figure so that you can get the handles from that.

Answer 1

[Geoff Hayes]

sufyan - suppose that your timer starts when you press the start button in your GUI. The pushbutton callback would look something like

 function start_Callback(hObject, eventdata, handles)

 handles.timer = timer('Name','MyTimer',               ...
                       'Period',1.0,                   ... 
                       'StartDelay',0,                 ... 
                       'TasksToExecute',inf,           ... 
                       'ExecutionMode','fixedSpacing', ...
                       'TimerFcn',{@timerCallback,handles.figure1}); 

 guidata(hObject,handles);
 start(handles.timer);

The above timer will fire (roughly) every second. Note how we pass the GUI figure handle as an input to the timerCallback function. This is necessary so that we can access the handles structure (from there) to (potentially) update the axes with new data. The callback can be defined as

 function [] = timerCallback(~,~,guiHandle)

 if ~isempty(guiHandle)

      % get the handles
      handles = guidata(guiHandle);

      if ~isempty(handles)

          % use EEG handles.data (?) to update the axes

          % if new data, then update the axes

      end
  end

In the above, we get the handles structure using guihandles so that we can get the current set of data in the axes control. In your stop button callback, you would then stop the timer

 function stop_Callback(hObject, eventdata, handles)

 if isfield(handles, 'timer')
     stop(handles.timer);
 end