Thread: Master clock to control Stimtracker through TTL input View Single Post
QinXinlan
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Join Date: Apr 2017
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Hello,

I am trying to set-up an experiment where EEG, eye-tracking signals and a high-speed camera all record data simultaneously.
Our lab already has Neuroscan for EEG acquisition, Tobii TX300 for eye-tracking with Stimtracker, and a Phantom M310 for the high-speed camera. We also have the E-prime software with the Extension for Tobii.

I need to setup a master clock that would send event markers to both Neuroscan and Tobii, as well as control the high-speed camera. I (nearly) already solved the problem of linking all the equipments and send the Event Markers as well as the control signal.
My problem is the timing of this master clock. At first, I though I would use the light sensor provided with the Stimtracker, and display a black or white rectangle on the Tobii TX300 screen. However I need to send markers every 4 ms, and the vertical sync frequency of the Tobii TX300 screen unit is between 49 and 75 Hz, so not fast enough.

Thus I thought of using an Arduino as the master clock, which would send a 5V square-wave signal with a 4 ms period to the TTL input on Stimtracker trough an Ethernet cable (RJ45). Does that work in theory? Can Stimtracker receive and process such a "fast" signal?
Also do you have any other suggestion on how to create this master clock? The easier the better.

Thank you very much for your advice.
Best regards,
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