Device for detecting the presence of an object or of a living being

An installation for closing an opening contained in a building or a swimming pool and which comprises, on the one hand, lateral runners designed to be positioned facing one another, on either side of the opening and, on the other hand, an apron designed to close the opening and having lateral ends mounted slidingly inside the lateral runners, characterized in that it also comprises a device for detecting the position of the apron between two terminals, this detection device comprising:

• a means for transmitting an electromagnetic signal comprising, on the one hand, a transmit antenna, associated with a first terminal, and adopting the form of a tubular waveguide having at least one wall provided with at least one opening and, on the other hand, a means for exciting this antenna for the purpose of transmitting such a signal via this antenna;
• a means for receiving this electromagnetic signal comprising, on the one hand, a receive antenna, associated with a second terminal, adopting the form of a tubular waveguide having at least one wall provided with at least one opening and, on the other hand, a means for detecting such a signal;
• a means for determining the position of the apron by analyzing a received signal received by the receive means as a function of a control signal from the transmit means, this received signal and this control signal being connected by a transfer function dependent on the position of the apron.