stimulus-onset markers in SMI .idf file

Comments

• cesco

  February 2019 edited February 2019

  Your sync question is tricky, because with SMI I don't think it's possible to sync the clocks. However, you can definitely send timestamped markers to iViewX directly. It's in fact fairly straight-forward by adding a few lines in your libsmi.py script:

  def send_message(self, msg):
      iViewXAPI.iV_SendImageMessage(c_char_p(msg))
      # print command to debug window is optional:
      print("message: ", msg)
  

  You can then used send_message in your script where you want to send a marker instead of the log function, and it will show up in your IDF file with the SMI timestamp.

  Hope this helps!

  I just sent this as a pull request to @Edwin too, so you might see it in the master branch soon.
• Russell

  August 2019

  Thanks so much, Cesco and Edwin!
  I know there has been a long delay, but I'm stuck and have a very newbie question.

  When you said I can use send_message in my script, do you mean an OpenSesame inline-script item? So I would create an OS inline-script item named "stimulus_marker_script" and I would put the one-line Python instruction in the run tab of the OS GUI?

  For instance, with the code you sent in libsmi.py, and with the following in the run tab of the OS inline-script GUI

  self.send_message(stimulus_presented)

  the inline script "stimulus_marker_script" would add an SMI timestamp and the string "stimulus_presented" to the IDF file everwhere I insert it in the Open Sesame experiment?

  Sorry to be such a slow learner
• cesco

  August 2019

  You're definitely on the right track!

  If you have the latest OpenSesame release, you don't need to do anything with the code in libsmi.py, as it has since then be committed to the master branch of Pygaze.

  Indeed, wherever you want to send a marker you simply insert an inline script, and in the run tab you write:

  eyetracker.send_message("stimulus_presented")

  (Notice the minor differences with your suggested code above)

  And again correct: this message will be in your IDF file with the timestamp. Make sure to test and check like usual. :)

  Keep me posted!