Get our experiment running first 
In a colleague’s laboratory there is a delay of 34 ms between trigger and visual stimulus. He has no idea what is causing this. This is a lot if you are interested in early ERP components Start reading from page 19 of the PsychoPy manual https://www.psychopy.org/PsychoPyManual.pdf
Best wishes Jens
Hello! An update on the same, we connected the EEG Gtec and ran the experiment. When we add time (s) - 0 the experiment runs fine and we can also see the triggers int he recording system. But when we add conditions and add image.status == STARTED and other details. We were not able to see the triggers at all. Could you Possibly guide here?
Hi @Yashpreet_Kaur,
What happens if the condition is only image1.status == STARTED? Is there a reason you’re adding the 0.01s delay?
What happens if you increase the duration of the trigger pulse from 0.05s to 0.1s (after changing the start condition to image1.status == STARTED)?
Hey! we have tried the latter, but it doesn’t seem to be working even now. But like I mentioned before, the triggers are getting recorded when we set the start as time(s)- 0, so the nature of our paradigm is such wherein all the stimuli appear on the screen at the same time, noting that there is no delay in presentation of any stimuli as such. In the center there’s a fixation cross surrounded by two images one on the left and one on the right. And we aim to record triggers for both the images which are presented at the same time on both the sides for 150 ms on screen. Now that the start setting as condition is not really working out, could we possibly continue with time(s) but rather set a start time as 0.01 or 0.02 instead of keeping it 0 for each routine?
Thank you for your guidance all along!
hey! would you have anything to suggest on the recent doubt I posted?
Thank you so much!
Hi @Yashpreet_Kaur,
I would certainly not recommend setting a start time of 0.01/0.02 because that is definitely not going to send your trigger at the same time as your stimuli.
If you set the start time to 0, I would very strongly recommend that you test the timing of the trigger using a photodiode before collecting any data. Please carefully read the manual that @JensBoelte linked to earlier in the thread to help with that. I would strongly recommend that you do that anyway before you collect any data.
The trigger should send though, if the image status is started, I can’t see a reason from what you’ve shared that it shouldn’t.
Hello
What happens when you set the start-time of all your component to a time different that 0 ms? You could start the routine with presenting the fixation cross instead of starting it with the images. You need an ISI or ITI anyway which you could cooperate in your routine.
And again, why do you use two parallel port-components?
Best wishes Jens
hello! our experiment is running fine, we were incorrect with using 2 parallel ports in one routine, your constant suggestion helped.
@JensBoelte
Thank you for the link to manual, we looked into the intricacies and got it working!
Now we are only using one parallel port in each routine.
Although we have not tested the timing of trigger using photodiode because that seems a little complicated for us to do.
But the triggers are seen so far and the expeirment is functional. In that case not using photodiode should be fine right?
Hello @Yashpreet_Kaur
good to read that your experiment is up and running.
Sure, you just don’t know if there is a delay between the trigger and the visual stimulus 
But I understand that it is too much trouble if you do not have access to the equipment. I mention two papers in this post Question about using Cedrus SV-1 Voice Key with PsychoPy (v2024.2.4) - #2 by JensBoelte that deal with this timing issue, one deals with voice keys, the other deals with timing on a more general level.
In a colleague’s lab there is a delay of 34 ms between the parallel port trigger and the visual stimulus.
Best wishes Jens
