This dissertation investigates in a multidisciplinary way the process of facial expressions animation in stop motion feature films. It contextualizes and observes the production of stop motion feature films in Brazil and abroad. Through exploratory and experimental research, we investigate physical interface technologies applied to puppet s facial expressions animation. The research is structured in three parts. First, stop motion technique is discussed through a historical parallel between technological development in relation to the technique. Next, information is gathered on feature film productions, from Brazil and abroad, using stop motion technique with puppets. Different techniques found in facial expression animation are observed in relation to the character s interpretation and the unity of the puppet. The survey starts with a bibliographic review and interviews with four national studios in the production stage of stop motion feature films in the last part, we discuss the act of animating a puppet and propose a series of experiments in search of new ways to animate the facial expressions of puppets with the aid of technology. The experiments were based on processes of reflexive practice, knowing-in-action and reflection-in-action. This research contributes to the expansion of the discussion about the stop motion technique in Brazil, its optimization and production, thus motivating the production of new stop motion feature films in the Brazilian market.