eyelink.py improvements pushed -- needs more

[dmedine]

To all the eyelink users out there:

I recently had to add some features to our rather feeble eyelink connection client. What would be ideal is to create a full blown Qt driven GUI wherein the user can easily configure the behavior to his/her needs. Right now, I implemented the ones that best suited our scenario. This, of course, requires access to the eyelink python SDK, which is very good and fairly well documented.

The one thing that is tricky about this is timing. Eyelink.py uses calls to sleep() as the clock (which is highly jittery). We found that decreasing the sleep time to below the sampling period of the eyelink did not result in expected behavior. I think in the end we clocked it to somewhere close to the sampling period and included the eyelink timestamps as one of the data channels. This way, the original data timing can be fully recovered from the data. All in all this is not ideal, so this guy can use some work.

I don't know how many people are needing this, but I thought I would start a discussion just in case.

[idahlstromhakki]

Thank you for starting this discussion thread. I've actually made some changes to the eyelink.py code to push event data to the stream and to translate the eyelink timestamps into local timestamps at the ms level. I'm currently traveling so I am not able to upload the code just now but I am very interested in improvements and happy to contribute where I can. I'll try to clean up the code a bit and add comments before posting.