Abstract: This study presents the design of an algorithm oriented to the setting of the state of fatigue in a person, based on free software programming tools. It is possible to reproduce the behavior of the state of fatigue and recovery through an open algorithm, that is that can receive information from different sources of acquisition be it visual, electrical or statistical. We obtain a result whose efficiency depends on the source of information for the case it was validated by a video acquisition system using image processing techniques and for which it yields an accuracy in the detection of fatigue of 94.5%.