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hamed_neu

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Reply with quote  #1 
The Eyelink has a digital output which can be sent by Ethernet protocol. Psychotoolbox has a bunch of Matlab codes for online reading x and y of the eye.  Is there any opportunities to use these codes in timing file. By doing this we can have a better SNR for eye position and even decrease the delay. One issue I had is that the mex files for interfacing with Eyelink are 64 bit while the matlab I used is 32 bit. Is there any way to do this and could it enhance the performance?
       
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Wael.Asaad

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Reply with quote  #2 
We haven't tried to interface yet with the ethernet output of eyelink.  Typically, ethernet and USB have packet delays that make them less than ideal for near-real-time behavioral monitoring.  Unless the Eyelink has an internal delay that's greater for analog than for ethernet, usually the analog output is faster and has reliable, fixed timing delays.  Do you know what the delays are for the Eyelink outputs via ethernet vs. analog, and their variability?


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ryklin

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Reply with quote  #3 
We could add a digital eye tracker(s) to the DigitalInputStream adapter I built for USB touchscreens. However, exactly as Wael said, we do not know what the latency characteristics are for the Eyelink ethernet output and we should assume it performs worse than analog output. Maybe things have changed with Gigabit ethernet, or 100 baseT. If we decided to do this, we could add connectivity for many eyetrackers not just EyeLink. Better yet, we could provide a simple programming interface that would allow users to implement it for their own eyetracker themselves. I know of a lab that built their own digital eyetracker from scratch and integrated it into MonkeyLogic with excellent results (that doesn't guarantee the Eyelink will run that well).

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maloman

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Reply with quote  #4 
Hey all,
I have discussed the Ethernet latency issue with Eddy before and on my home brew eye tracker nidaq c++ lib vs zeromq Ethernet lib did not make much of a difference. I had round trip (hardware tested with switching LEDs) latencies lower than 2ms. Ethernet has extremely low latencies potentially lower than analog output due to better integration. The key is to implement it into ML in a way that this edge is preserved. Another advantage of the digital would be no signal degradation even though 14 bit analog should be more than sufficient.
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coxma

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Reply with quote  #5 
Chiming in with a vote for this feature. We use eyelink and essentially have to calibrate twice, once on the eyelink size and once on the ML side, which wastes juice and time. 
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Jaewon

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Reply with quote  #6 
Hi coxma,

You can make MonkeyLogic skip the calibration and take whatever signal EyeLink provides as it is. Then just one calibration on EyeLink should be good enough.
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ryklin

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Reply with quote  #7 
Hi everyone,

I agree with Jaewon regarding double calibrations being unnecessary. Just calibrate in the EyeLink system.

Regarding properly integrating digital eye trackers, we will get back to you soon.

Thanks!
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bcorrigan

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Reply with quote  #8 
Hi,
So I know that this is an old topic, but we are looking at starting to use ML, and are interested in the ethernet connection with eyelink. Has there been any progress on this front? Thanks for any replies!
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Jaewon

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Reply with quote  #9 
I have many Arrington trackers, so I am looking into their ethernet link. I don't have any EyeLink system, but I will try to support it since I know many people use it.
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Jaewon

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Reply with quote  #10 
Now NIMH ML2 supports Ethernet links for Arrington ViewPoint EyeTracker and SR Research EyeLink.

http://forums.monkeylogic.org/post/nimh-monkeylogic-2-8444337?pid=1302275002
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