A sensor assembly includes: an electrically insulating and flexible body (13), in the form of a plate having a first face (13a) and a second face (13b) and a first sensor (15 315) and a second sensor (17), which are incorporated in the body (13). The first sensor (15) is set between the first face (13a) and the second sensor (17), and the second sensor (17) is set between the first sensor (15) and the second face (13b).
