A SENSOR DEVICE FOR DETECTING THE PRESENCE OF AN ELECTRICALLY CONDUCTIVE SUBSTANCE IN A SPACE REGION, AND APPLICATIONS THEREOF
The sensor device (1) for detecting the presence of a body or substance in a spatial region (A) comprises detecting circuit means (2), including at least first and second foils or sheets (A, B) of an electrically conductive material; and control circuit means (MC) coupled with said detecting circuit means (2) and having an output (4) connected with one (B) of said foils (A, B) for applying a first electric radiofrequency signal thereto and an input (6) connected to other one (A) of said foils (A, B) for receiving a second radiofrequency signal induced in said other foil (A); said control circuit means (MC) being arranged to generate an information signal indicative of the strength of said second signal, which varies as a function of the presence of a body or a substance on or at said other foil (A).