| Reference | Downloads | Github

Builder timing concerns for sending EEG triggers

Hey there,

I’m currently building a task using the Builder where I’ll be sending a couple of triggers per trial and I was wondering whether using parallel port components with start times set to the same start time as my image stimuli (e.g. 0s, 0.750s, 1s) is guaranteed to send the triggers synched to the image stimulus flip or whether it is better to split a single trial into a couple of routines, (one for each trigger that is going to be sent).

Thank you in advance.

Hi @mkallmayer, if you use frames instead of seconds to time your stimuli and parallel port, the parallel port will fire on the first instruction to draw your stimuli. Ensure that your parallel port is set to “sync to screen” in the Parallel Port component dialog box. To be sure, read the following links about PsychoPys timing capability, and also check whether you are dropping frames during the stimulus presentation.

Can stimuli appear at a precise rate
Detecting dropped frames
Specific timing

1 Like

Thank you!