Abstract. This paper presents the development of a prototype to avoid forgetting children inside vehicles. Brazilian reports have recorded 21 deaths of babies and children between 2006 and 2015 caused by vehicular hyperthermia. The prototype, that is described in this paper, will alert the responsible if he distances himself of vehicle and a child is left in baby seat, making it possible to safely remove the infant. For the development of prototype, will be used the Arduino prototyping plataform, because it's costs is low and it has a fast learning curve.