[solved] Collecting number of keypresses in a fixed amount of time

Comments

• Edwin

  March 2014 edited March 2014

  Hi!

  In theory, you could do this using the GUI, but you'd end up with massive data files! The easiest solution would probably be to use the following code in an inline_script item:

  # import the keyboard class, to be able to
  # poll the keyboard
  from openexp.keyboard import keyboard
  # import numpy, which we will use to do
  # some calculations with
  import numpy
  
  # initialize a keyboard instance
  kb = keyboard(exp, keylist=['1'], timeout=10)
  
  # create an empty list, to store the keypress
  # times in (so we can use those later)
  presstimes = []
  
  # let the user smash your keyboard for 8 seconds!
  t0 = self.time()
  while self.time() - t0 < 8000:
      # wait for a keypress
      keypress, presstime = kb.get_key()
      # add the press time to our list
      if keypress:
          presstimes.append(presstime)
  
  # convert the list of keypresses to a numpy
  # array of keypresses, to make calculations
  # easier to do
  presstimes = numpy.array(presstimes)
  
  # after the frenzy, convert the keypress times to
  # reactiontimes, by calculating the difference
  # between each presstime (using numpy.diff)
  intresptimes = numpy.diff(presstimes)
  
  # calculate the mean and standard deviation
  # of the inter-press times
  M = numpy.mean(intresptimes)
  SD = numpy.std(intresptimes)
  
  # some more descriptives: the amount of
  # presses and the standard error of the mean
  N = len(intresptimes)
  SEM = SD / (N**0.5)
  
  # save the variables so that they can be used
  # in OpenSesame's GUI
  exp.set("Nipt", N)
  exp.set("Mipt", M)
  exp.set("SDipt", SD)
  exp.set("SEMipt", SEM)
  

  Keeping track of how long the button was down, is not possible in this way. You'll have to directly use either PyGame or PsychoPy to do so.

  Good luck!
• alberhernandez

  March 2014 edited 3:58AM

  Thank you very much Edwin!

  I'm experiencing this problem when trying to run the experiment with the given code:

  Error while executing inline script
  
  phase: run
  item: inline_script
  line: 9
  exception message: __init__() takes at least 2 arguments (3 given)
  exception type: TypeError
  
• Edwin

  March 2014 edited March 2014

  My apologies, that's due to a silly mistake (forgot to pass exp to the keyboard!). I've edited my previous post, so it should work now.
• alberhernandez

  March 2014 edited March 2014

  Thank you very much. It works like a charm.