The aim of this paper is to address the issue concerning the tools for getting feedback from e-learning platform users. Our research analyzes the role of human presence in mediated learning environments proposing a possible strategy to detect it. The proposed system is based on web 2.0 patterns that are suitable for activating a virtual classroom tool with a feedback system to evaluate the student's presence. Through specific sensors this human presence detector is employed to assess student participation in the framework of an e-learning 2.0 platform that was developed for precise academic purposes. The system is based on the use of a distance measurement device and an air quality measurement device. The use of a FIS is, then, proposed to resolve disambiguation of presence/absence detections.