This paper presents a prospective ergonomic approach that allows us to evaluate a new pervasive technology (CIRDO) for the home care of dependent elderly persons. The aim of this technology is to empower these persons by the detection of their physical falls (via audio and video sensors) and to alert their family or care givers. In light of the activity theory model, we developed a prospective approach in the real environment of the elderly that aims to help us to reflect upon the conception and design of future things and to understand the way in which each person in the system could benefit from such a contrivance. In order to understand these effects, we developed a methodological triangulation approach by involving various techniques of data collection such as semi-structured interviews, focus group, analysis of the activities of daily living conducted at seniors homes, script falls methods, simulation of incidents by the elderly, observations filmed with simultaneous verbalization techniques and Personas method, We show that the implementation of CIRDO has an impact on the activity of each person in the home (elderly persons, family, professional care-givers) and could also redefine the relation-ships between different systems of activity, requiring each participant to adjust and re-position his practice, status and commitment in the area of habitation. In this context, our contribution is not only to imagine the uses, but also to explore the social function associated with this new tool.