Wait for a key press or move on with next trial

Hi, I'm using psychtoolbox to run an experiment. I need to wait for a partecipant key press. If any key is pressed after 2 seconds, move on to next trial. I have this code:

          while (StimTime-starttime)<=StimTime 
              [KeyIsDown, endtime, KeyCode]=KbCheck;
               if KeyIsDown && (( side(abstrial)==1  && KeyCode(leftKey)==1) || (side(abstrial) ==2 &&  KeyCode(rightKey)==1))
                  rt(abstrial)= (endtime-starttime); %Compute reaction time
                  ac=1
               end
               if KeyIsDown && (( side(abstrial)==1  && KeyCode(rightKey)==1) || (side(abstrial) ==2 &&  KeyCode(leftKey)==1))
                  rt(abstrial)= (endtime-starttime); %Compute reaction time
                  ac=0
                  textWA =  strvcat(['Risposta sbagliata']);
                  DrawFormattedText(win, textWA, 'center', 'center', [255 255 255]);
                  Screen('Flip',win);
                  pause(.3);
               end
               if KeyIsDown && KeyCode(rightKey)==0 && KeyCode(leftKey)==0 &&KeyCode(escapeKey)==0;
                  textWB =  strvcat(['Ops, tasto sbagliato']);
                  DrawFormattedText(win, textWB, 'center', 'center', [255 255 255]);
                  Screen('Flip',win);
                  pause(.3);
               end
              if KeyIsDown && KeyCode(escapeKey)
                  ShowCursor(win);
                  Screen('CloseAll');
              end
             break
  end

I' ve tried to add waitsecs(2) after the stimulus' flip but it doens't work. I've also tried with

if endtime-startime> 2 
end

But this doesn't work too!

How could I add the maximum time of 2 seconds within the while loop?

Thanks!

[Jan]

Note:

textWB = strvcat(['Risposta sbagliata'])

??? What about:

textWB = 'Risposta sbagliata';

Answer 1

[Jan]

What is endtime, StimTime, starttime? You have posted a lot of code, which is not related to the actual question, but not the important details.

KeyIsDown = false;
starttime = now;   % Perhaps, or a PsychToolbox function?!
while (now - starttime) <= StimTime || KeyIsDown
  [KeyIsDown, endtime, KeyCode] = KbCheck;
end

if KeyIsDown
  ... % Process the pressed key
else
  ... % Time out while waiting for a key press
end

[Laura Pizzato]

    [starttime]= Screen('Flip',win); %Start recording reaction time with 
    stimulus flip
    endtime = KbQueueWait();  % Wait a Keypress
    StimTime=GetSecs;

[Jan]

Sorry, I do not have the PsychToolbox installed and do not know any of the shown commands. Perhaps you want to replace the now in my suggestion be GetSecs.

[Walter Roberson]

KbQueueWait() accepts a maximum wait time as its third parameter. I cannot tell, though, whether it is expecting an absolute time (in what time base?) or a relative time (in seconds?)