Stimtracker and EGI - timing tests

Hi there!

I am running a project that I inherited from a researcher before me. They were unaware of the necessary updates for using the stimtracker in conjunction with EGI Netstation, so a large amount of data is unusable. Me and my coworker are trying to recover the data as it is time-locked and we need a precise offset for it to work.

We are running a checkerboard flip paradigm - board 1 is shown for 500ms and then board 2 is shown for 500ms for 400 trials. The stim tracker drops DIN 1 for both boards. Before the EGI update we believe the DIN was dropping at the end of the trial instead of the beginning. However when analyzing our data we’re finding anywhere from a ~300ms to 400ms delay in our data.

We’re presenting in E-prime 2.0 but it does not talk to Netstation so we are only marking the stimulus presentation with the stimtracker, meaning we do not have a “fixed” marker to compare the offsets to. We have tried having a 500ms offset to our data but the data is still very wrong.

Is there a way to run a timing test to compare the differences between the two set ups? I’m thinking of turning on the USB output, running the experiment the wrong way and then running it the right way and subtracting the times from the two but am unsure if that is the best way to go about it. Thanks so much in advance!

I’m not sure. Please send us an email. This would be faster discussed over a zoom meeting.