[Eeglablist] Need some technical help

[전성택]

i know that this is a forum specifically for the eeglab, but i need desperately help on technical issue. i'm using portable eeg system which comes with a photic port behind the system. i'm using a photocell  to synchronize eeg signal with event in a separate monitor. basically, i draw a small square patch at the corner of the experimental monitor whenever experimental stimulus is on. the white patch flashes once for a single refresh when the stimulus is on, and it stays black until next stimulus is delivered. what the photic port is supposed to do is to detect the voltage change across the photocell while the luminance of the patch changes. the problem here is, i don't get 100% event recovered from the eeg. at this point, i've tried to optimize the luminance range for the photocell that i'm using by adjust the monitor brightness and contrast (i even open up the monitor and play around with the factory settings), i tried a potentiometer to the photocell in parallel, tried dif!
 ferent ph

otocells and monitors but nothing really worked. is there anyway to make it super reliable with photocell or should i come up with different way to synchronize the events? any help will be greatly appreciated.


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