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.
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.