To increase a user's satisfaction level when using an entertainment system it is extremely interesting that this system has the ability to obtain feedback from the user in real time. The emotional state of an individual is able to change his physiological systems behaviour. This paper proposes to analyze a physiological signal obtained through the photoplethysmography. The signal is collected using the multiparametric affective gamepad called Emopad. Furthermore, a heuristic is proposed to be implemented on the Emopad, to process and classify moments of scare an individual has while watching a scary video.