Record blink rate via laptop webcam before, during, and after a task?

[Jessica McGovern]

Hi all,

I'm trying to code a paradigm with E-Prime 2.0 Professional to record blink rate at different intervals (e.g., baseline, during task, and post-task) and I need to find a creative solution for coding this, especially since I have limited prior coding experience. The simplest, most low-tech, solution I could think of is record the participant's face throughout the entire task and play a (non-jolting) sound to demarcate the start and stop periods for counting blinks upon later replay, with the thought that trained RAs can manually count them afterward. The recording periods will be brief - 5 min. or 1 min. A more sophisticated solution would be to somehow communicate to the webcam device or video recording software to demarcate start and stop times for each period of recording. Part of the reason I am not using eyetracking software is that the task needs to be easily transportable to multiple sites and I want to minimize the amount of lost data I could potentially have due to technological difficulties. I was thinking that some sort of Signal Port solution might apply, but I am unsure of both the coding logistics and the technical logistics to set this up (e.g., is there a specific type of video recording software (preferrably free or cheap) I need to download?). Any guidance on how to record blink rate at different intervals would be greatly appreciated.

Thanks,

Jessica