Trigger Servo Motor in a specific frame in a Video [Exoskeleton]

I am trying to build a hand exoskeleton with the aim of rehabilitation. The idea is activating a persons mirror neurons through a video and a hand mechanism (which has a servo motor that mimics the finger motion).

I am using Arduino [UNO] for operating the servo motor. My current obstacle is triggering the servo motor through a specific frame in a video (which shows the finger motion of a person).

This is my first experience using PsychoPy so I have very little knowledge about it. However if someone could lead me in the right direction i would be really thankful.

com-video-to-gif