OpenSesame

Two-second delay after logger in OpenSesame

The result shows a varying delay of around 2 seconds on average. It would be very helpful for us if we could cut down this delay, as it adds up. To try to achieve this, I reduced the number of variables logged, from the default 363 to 34 important variables. Unfortunately, this change did not result in a reduction of the delay.

An inline script for OpenSesame to send EEG triggers via serial port

The OpenSesame user base is skyrocketing but—of course—remains small in comparison to many other user bases that we are used to. Therefore, when developing an experiment in OpenSesame, there are still many opportunities to break the mould. When you need to do something beyond the standard operating procedure, it may take longer to find suitable resources than it takes when a more widespread tool is used. So, why would you still want to use OpenSesame?

How to correctly encode triggers in Python and send them to BrainVision through serial port (useful for OpenSesame and PsychoPy)

I'm sending the triggers in a binary format because Python requires this. For instance, to send the trigger 1, I run the code serialport.write(b'1'). I have succeeded in sending triggers in this way. However, I encounter two problems. First, the triggers are converted in a way I cannot entirely decipher. For instance, when I run the code serialport.write(b'1'), the trigger displayed in BrainVision Recorder is S 49, not S 1 as I would hope (please see Appendix below). Second, I cannot send two triggers with the same code one after the other. For instance, if I run serialport.write(b'1'), a trigger appears in BrainVision Recorder, but if I run the same afterwards (no matter how many times), no trigger appears. I tried to solve these problems by opening the parallel port in addition to the serial port, but the problems persist.

Intermixing stimuli from two loops randomly in OpenSesame

I’m developing a slightly tricky design in OpenSesame (a Python-based experiment builder). My stimuli comprise two kinds of sentences that contain different elements, and different numbers of elements. These sentences must be presented word by word. Furthermore, I need to attach triggers to some words in the first kind of sentences but not in the second kind. Last, these kinds of sentences must be intermixed within a block (or a sequence) of trials, because the first kind are targets and the second kind are fillers.

Assigning participant-specific parameters automatically in OpenSesame

OpenSesame offers options to counterbalance properties of the stimulus across participants. However, in cases of more involved assignments of session parameters across participants, it becomes necessary to write a bit of Python code in an inline script, which should be placed at the top of the timeline. In such a script, the participant-specific parameters are loaded in from a csv file. Below is a minimal example of the csv file.