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Confirming Stimuli Duration (~20ms)/ Timing Test

briefpresentations
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timing

#1

Hello all,

I just wanted to check in and ask about PsychoPy’s stimuli presentation. We are doing some low-level vision research and will be presenting images on a ViewPixx (running at 120Hz). My lab has calculated that we should have our stimuli appear for only 2 frames (technically making it ~16ms).

Now that I’ve got the theory fleshed out, I am curious to find out how many of you all been able to confirm that the stimulus appears for that duration of time. On a similar topic, is there a timing test I can run to calculate drift between PsychoPy and Netstation. I am not sure if this is helpful, but I have the diode that came with NetStation Amp (EGI).

Thanks!
Laur

*Note I am not entirely sure where this question should go, so I apologize in advance if it is in the incorrect category


#2

We use PsychoPy with a 60Hz monitor and I can confirm that it does draw at that rate. We are using an Arduino to record frame timestamp data sent from the program, which has been consistent with photodiode response collected at the site of our stimulus. I am not familiar with Netstation, but if you can collect the output of your timestamp side-by-side with a photodiode you should be able to see if there is any drift.


#3

Thanks jtrinity, that sounds like a good idea. I’ll try that out, and reply back with how that works.