MATLAB: How to count key presses in limited time

guiguide

my task is using a GUI, to count during 10 seconds the times the subject pressed on the spacebar . after building a GUI that gets the subject's id, it makes a text visible that says- " the 10 seconds will start when you press the spacebar for the first time"

now- where in the code (in which function) I have to put the timer and counter orders? and how do I make a counter that works for a limited time of x seconds.

I guess i need to use somehow the keypress and keyrelease functions although I am not too fimiliar with them..

Best Answer

Oh, you need timer objects and a key press function brah! Also, you gotta stop thinking in loops and start thinking in callbacks!

Check out the example below...

Some key points

1. Listen to the figure to see when a key is pressed

figure('KeyPressFcn',@youPressedSomething)

2. Use a timer object with callbacks that control a state variable

t = timer(...)

There's good documentation on both these things brah!

http://www.mathworks.com/help/matlab/ref/figure_props.html

http://www.mathworks.com/help/matlab/ref/timer.html

Also I made a typo when typing "spacebar" and changed it to "spacebrah" and thought it was funny so I kept it going in this post (hence me saying "brah" a lot)

http://oxforddictionaries.com/definition/english/brah

Example:

function youPressedSpaceBrah
%Create figure and text box
fh = figure('DeleteFcn',@cleanUpTimer,'KeyPressFcn',@youPressedSomething);
th = uicontrol('Parent',fh,'Style','text','Position',[10 10 300 30],...
    'String','You have not hit space yet');
%State variables
count = 0;
allowCounting = false;
%Timer
t = timer('StartDelay',10,'TasksToExecute',1,'StartFcn',@timerStarted,...
    'TimerFcn',@timerFinished);
%Callback functions
      %When the user presses a key
      function youPressedSomething(~,eventdata)
          %See if it is the space bar
          if strcmp(eventdata.Character,' ')
              if allowCounting
                  count = count+1;
                  set(th,'String',['You hit space ' num2str(count) ' times brah!']);
              else
                  startTimer;
              end
          end
      end
      %Kick off the timer!
      function startTimer
          start(t);
      end
      %Callback for when timer starts
      function timerStarted(~,~)
          count = 0;
          allowCounting = true;
      end
      %Callback for when timer finishes
      function timerFinished(~,~)
          allowCounting = false;
      end
      %Cleanup (delete timer object)
      function cleanUpTimer(~,~)
          stop(t);
          delete(t);
      end
end

Related Solutions

MATLAB: How to count key presses in limited time

I would do it just like I showed you before, but add a keyreleasefcn. So when the user pushes the correct key, a value is set. Subsequent calls to the keypressfcn are ignored unless the value is unset by the keyreleasefcn. For example (recall you may want to use windowkeypressfcn and windowkeyreleasefcn instead...):

function youPressedSpaceBrah2
%Create figure and text box

S.tm = 0;
S.tm(2) = 1;
S.fh = figure('KeyPressFcn',@youPressedSomething,...
              'KeyReleaseFcn',@youReleasedSomething,...
              'menu','none',...
              'pos',[400 400 320 50]);
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
                'String','You have not hit space yet');
S.cnt = 0;  
S.R = 1;
      function youPressedSomething(varargin)
          %See if it is the space bar

      if ~S.R
          return
      else 
          S.R = 0;
      end
      S.tm(2) = now;  % Holds current time.

      if diff(S.tm)*86400>10 % Greater than 10 secs?

          S.tm(1) = now;
          S.cnt = 0;
      end
      if strcmp(varargin{2}.Character,' ')
          S.cnt = S.cnt + 1;
          set(S.th,'str',sprintf('You hit space %i times brah!',S.cnt));
      end
      end
      function youReleasedSomething(varargin)
          S.R = 1;
      end
  end

Here is another example. This one does not use nested functions, so it is more like what you might find when working with at GUI built by GUIDE. Notice that I use the GUIDATA function throughout. Your code will differ, of course, but I think you can get the idea....

function youPressedSpaceBrah3
%Create figure and text box
S.tm = 0;
S.tm(2) = 1;
S.fh = figure('KeyPressFcn',@youPressedSomething,...
              'KeyReleaseFcn',@youReleasedSomething,...
              'menu','none',...
              'pos',[400 400 320 50]);
S.th = uicontrol('Style','text','Position',[10 10 300 30],...
                'String','You have not hit space yet');
S.cnt = 0;  
S.R = 1;
guidata(S.fh,S)  % Store the handles.
function youPressedSomething(varargin)
%See if it is the space bar
S = guidata(gcbf);  % Get the structure

if ~S.R
    return  % User has not released the spacebar....
else
    S.R = 0;
end
S.tm(2) = now;  % Holds current time.
if diff(S.tm)*86400>10 % Greater than 10 secs?
    S.tm(1) = now;
    S.cnt = 0;
end
if strcmp(varargin{2}.Character,' ')
    S.cnt = S.cnt + 1;
    set(S.th,'str',sprintf('You hit space %i times brah!',S.cnt));
end
guidata(gcbf,S) % Save the structure

function youReleasedSomething(varargin)
S = guidata(gcbf);  % Get the structure
S.R = 1;
guidata(gcbf,S) % Save the structure

MATLAB: How to count how many times a button was pressed

Joana,

If I understand your question correctly, you want to consider 'Press and Hold' of any key as a single key press. But usually press and hold of a key is considered as multiple quick key press-releases of the same key. So as you can see in the below code I've used a simple tic-toc combination to check if the time between a key press-release of the same key is less than 0.05s(you can tune this time if you want), in which case I'm just printing the key count value at that point without any increment.

    function KeyPressAnalyze
    KeyPress_Main = figure;
    set(KeyPress_Main, 'KeyPressFcn',@KeyPress_Main_KeyPress_Callback, 'KeyReleaseFcn',@KeyPress_Main_KeyRelease_Callback);
    KeyPressCount = 0;
    PressedKeyCurrent = {};
        function KeyPress_Main_KeyPress_Callback(Handle, Event)
            tic;
            PressedKeyCurrent = Event.Key;
        end
        function KeyPress_Main_KeyRelease_Callback(Handle, Event)
            KeyReleaseTime = toc;
            disp(KeyReleaseTime);
            ReleasedKey = Event.Key;
            if (strcmp(PressedKeyCurrent, ReleasedKey) && (KeyReleaseTime < 0.05))
                disp(KeyPressCount);
            else
                KeyPressCount = KeyPressCount + 1;
                disp(KeyPressCount);
            end
        end
end

Please let me know if this fixed your issue.

Regards

Best Answer

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MATLAB: How to count key presses in limited time

MATLAB: How to count how many times a button was pressed

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