[solved] How to log the duration of a key press?

mtoro

Hello!
I've trying OS for less than a week, done the tutorial and would like to start making my own experiments in this platform, I used to use the psychophysics toolbox for matlab, wich was good, but pretty complicated to run under linux....
My question is:
How can I log the duration of a keypress, not just when it was pressed but for how long?

Thanks,

Good Look!

sebastiaan

Hi Mtoro,

Welcome to the forum!

Yes, that's possible. But you will need to refer directly to the libraries used by the back-end, because the openexp.keyboard module doesn't support "key up" functionality (I'll consider adding it, because it would be useful. So thanks for bringing this to my attention!)

For the pygame-based back-ends (legacy and opengl) the following piece of inline_script should do the trick (so you would use an inline_script rather than a keyboard_response to collect responses):

import pygame
from pygame.locals import *

key_down_time = None
while key_down_time == None:
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            key_down_time = self.time()
            break

key_up_time = None
while key_up_time == None:
    for event in pygame.event.get():
        if event.type == KEYUP:
            key_up_time = self.time()
            break
    
key_duration = key_up_time - key_down_time
self.experiment.set("key_duration", key_duration)

You can modify this inline_script to fit your particular needs, but at least it shows how to determine the duration (uptime - downtime) for a keypress.

For more information, you can refer to the pygame documentation:
http://www.pygame.org/docs/ref/event.html

For doing the same trick with the psychopy back-end, please refer to the psychopy documentation:
http://www.psychopy.org/api/event.html

Hope this helps!

Kindest regards,
Sebastiaan

mtoro

Many Thanks for the Answer!!

Will try it monday and comment on the results,

Great Job for OS,

Hope you have a good time!

Mauricio.

sebastiaan

Inactive, marking as solved.