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Presenting stimuli only while a button is pressed

edited September 2018 in OpenSesame

Hi to all,

I want to present a series of stimuli only while a certain button is pressed (i.e. the space button).
I already have the necessary part of the experiment for the presentation of the stimuli and the stimuli themselves.
Is there a way to do this?



  • Hi Amihai,

    There are multiple ways to do this, either with a script or coroutines item, but the easiest way depends on what you want to do exactly, and what you have programmed already. Could you upload the experiment here?


    There's much bigger issues in the world, I know. But I first have to take care of the world I know.

  • Hi Amihai,
    If you use an inline_script it may help to write a while loop, and ask for keylifts.
    You can find an example here:
    Good luck

  • Hi Sebastiaan, DahmSF,

    Thanks for the answers.

    Sebastiaan - I am attaching my experiment. Notice it is a bit "dirty" and has some scripts used for other purposes that I got from people in this forum (and for that I am grateful, I do not know how to code :smile: ). I want to add a script that will present the stimuli loop as long as the participant presses the space key. I would also appreciate advice on where to plant the script.

    DahmSF - I could not understand where is the example that you mentioned in the link you sent.

    Thanks again

  • Bump.
    Help anyone?

  • The example is in the experiment which is uploaded in the linked discussion. If you lift the button too early you get back to the beginning.
    --> There you need to keep the mouse button pressed, but you can easily change it to the space key on the keyboard.

  • DahmSF,

    I do not really know how to code so I cannot identify the specific part of the code that enables to present stimuli while a button is pressed. Can you point me to this part?
    Also, in my experiment, I measure the duration of the pressed button so it is a dependent variable. I do not want the experiment to go back to the beginning at any point. is the code in your example appropriate for this?


  • Hi Amihai,

    did you try the experiment i attached in the link?
    It contains not much more than pressing a button and keeping it pressed while some stimuli are presented.
    The duration you are asking for is easy to code. Just create a new variable: time of keylift - time of keypress.
    You can also look into the handbook for the keylift function Keyboard.get_key_release:

    Even if you do not want the experiment to go back to some point you need to specify what shall happen if a participant lifts the key too early. (I thought the best thing is to go back and start the trial again)

    You re welcome

  • Hi Stephan,

    I tried to take a look at the experiment but it did not work for me for some reason.
    I did look at the code in it though and saw that it is way above my level of understading.
    At this point, I think I will seek paid assistance.
    Do you know if there someone in this forum that offers such services?


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