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aboharbf

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Reply with quote  #1 
Hello,

I'm transitioning over to the runtime v2 way of coding tasks, and I also need to add something which doesn't fit as clearly and obviously into the new structure.

I'd like to add a photodiode to the lower right and upper left corners of the screen. Lower right for the entire duration of the task, and the upper left one for the duration of the sample.

before, it seemed a bit more obvious w/ toggleobject, but now, should I construct an independent scene for the entire task for the first photodiode, and simply add the 2nd photodiode to the "sample" scene?

Also, for finding the corner, is the best way simply trial and error given a fixed viewing distance?
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Jaewon

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Reply with quote  #2 
You know that the one in the lower right corner will flash later by one frame length than the one in the upper left corner, don't you?

The photodiode trigger that you can set on the main menu will turn on/off at the beginning of each scene, so you can use it for the stimulus duration. If you want a stimulus (the second trigger) on the screen all the time, you need to add it to every scene. If there is a gap between scenes, there are other ways to do it.

To find the corner position in degrees, calculate the distance from the center in pixels and then divide it by pixels per degree (ppd). ppd is shown on the menu.
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aboharbf

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Reply with quote  #3 
Quote:
Originally Posted by Jaewon
You know that the one in the lower right corner will flash later by one frame length than the one in the upper left corner, don't you?


Is that true even for a CRT? If so, perhaps I will re-position it.

Quote:
Originally Posted by Jaewon

The photodiode trigger that you can set on the main menu will turn on/off at the beginning of each scene, so you can use it for the stimulus duration. If you want a stimulus (the second trigger) on the screen all the time, you need to add it to every scene. If there is a gap between scenes, there are other ways to do it.


No Gap, so this may be suitable. It is a simple 2 scene set up at the moment - Fixation and then the stimulus immediately after.

Quote:
Originally Posted by Jaewon

To find the corner position in degrees, calculate the distance from the center in pixels and then divide it by pixels per degree (ppd). ppd is shown on the menu.


Fantastic, thank you for the tip. 
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Jaewon

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Reply with quote  #4 
Yes, it is true especially for CRTs. LCDs are no exception, either.
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aboharbf

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Reply with quote  #5 
Ah ok, thanks for the tip. The photodiode which can be introduced in the main menu - can it be set to respond to the stimulus instead of the overall trial?
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Jaewon

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Reply with quote  #6 
It is supposed to change its state when a new scene starts. I don't understand what you mean by the overall trial.
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aboharbf

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Reply with quote  #7 
I assumed the photodiode was switching every frame, so seeing the white square signified "on" and not being "off", but from what you've said, it is actually simply a white square which is "on" during scene 1, "off" during scene 2, etc. 
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Jaewon

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Reply with quote  #8 
Yes, it is on at the first scene, off at the second scene, etc. Usually the duration of the scene is the duration of the stimulus. You can make it switch every frame with the photodiode adapter.
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