This project, found in a 1981 documentation, consists of an interesting adaptation of the test nerve published in the book Games and Experiences with Electronics-Volume 5, which is shown in the figure. It is a sound alert system for the toy that allows the activation of a loudspeaker, in addition to the shock, when the player touches the ring on the bent wire. For those who do not know, the purpose of this game is to pass the ring through the wire without letting one touch the other, winning whoever reaches the end without being shocked or let the alarm ring.
