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marcnicklas
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Experiment start time, Posted May 6th, 2014 #1
Hi there!

I have a big problem that I hop you guys can help me with.

I need to know the EXCACT start of my experiment. Now, superlab gives me that information, but I need to know it in miliseconds. Superlab will write something like: "Experiment start: 14:32:28", but I need the miliseconds as well.

Since superlab can measure accurate response times (down to the milisecond) after experiment onset, the information I need must be stored somewhere in superlab.

But how do I access it?

I really hop you can help with this. My thesis depends on it
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MonikaT
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Posted May 8th, 2014 #2
I suggest using the Cumulative Time feature within SuperLab. This is found under the Experiment menu, Options, and Columns to Save. Every time that SuperLab executes an experiment, SuperLab tracks the ongoing duration in milliseconds. SuperLab begins counting from 0 milliseconds, and keeps counting upwards. If the Cumulative Time column is saved, it will be shown within the data file.

If this is not what you are asking for, can you describe the study that causes you to require this onset time? Are you trying to synchronize SuperLab's data with an EEG datastream?
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marcnicklas
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Posted May 8th, 2014 #3
The problem is, that I have two program running at the same time.

1) Superlab (running the experiment)
2) An eye-tracking program

Now, the eye-tracking program records the exact universal time, down to the milisecond, and I need to be able to syncronize the two. I can only do that by knowing the EXCACT starting point (down to the milisecond) of superlab.

Again, since superlab can measure cumulative time, it must record the actual starting time in miliseconds. But can I get access to it?
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MonikaT
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Posted May 9th, 2014 #4
SuperLab does have an accurate sense of response times, and also an accurate sense of "time since experiment onset." However, from the point of view of how SuperLab works, the timestamp of the onset time is simply "0" (this "0" has no notion of Month, Day, or Hour) .

The experiment start information in the header of the datafile was intended more as a convenience for distinguishing two data files that might be very similar except for the date and time at which they were gathered.

Can you tell me what eye-tracking software your using? Is this software running on the same computer as SuperLab or on a different computer?
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marcnicklas
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Posted May 10th, 2014 #5
Thank you for your reply.

The software runs on the same computer. The program is called Haytham (http://www.itu.dk/research/eye/?page_id=19) - it is an open source freeware program. I have build my own eye-tracker to use with the software.
'
Looking forward to your reply.

Best wishes
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MonikaT
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Posted May 15th, 2014 #6
We thank you for your request. We will keep your request in mind as we continue to explore new ways to integrate with other software and hardware.

For researchers using eye-trackers from Tobii, SMI, or ASL, the use of StimTracker solves the problem of having a common timebase:

http://community.cedrus.com/showthread.php?t=1982
http://community.cedrus.com/showthread.php?t=1894
http://community.cedrus.com/showthread.php?t=1641

However, since you have built your own eye-tracker you may be able to modify it so you can take advantage of one of the options below.

When trying to sync SuperLab to external hardware, there are two options. One is to have SuperLab send an electronic signal to the hardware, the second option is to have SuperLab receive an electronic signal from the hardware. When receiving an external signal, SuperLab will record a timestamp of when the signal happened, and presumably whatever is connected to SuperLab can also mark its own timestamp for the same signal.

In order to have SuperLab send a signal to the hardware, examine the options on these SuperLab event types:

Digital Output Event
Serial Output Event

To have SuperLab receive a signal, it might be possible to use Haytham to emulate a mouse. If so, then you can perform a mouse-click with the eye-tracker, and SuperLab will record this input in the datafile, together with a timestamp of when the click occurred.
Last edited by MonikaT; August 8th, 2014 at 01:31 PM..
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