Abstract: The present invention relates to a system for detecting characteristics of an elastic structure (13, 22, 23, 32, 33, 93, 1202, 1302, 1402), said structure being provided with at least one sensor (111, 112, 14, 211, 212, 311, 312, 911, 1211, 1311, 1411) and said system comprising at least one detector (16, 416, 516, 916, 1316, 1416). The sensor comprises a deformable member, which upon deformation generates a signal convertible to a signal representing said characteristic, said sensor further comprises a passive transmitter and said detector a receiver for receiving said signal representing said characteristic.