A sensor for, and a method of, generating electrical signals indicating a positional property and an extent property of a mechanical interaction within a sensing zone. The sensor comprises a plurality of conductive layers. At least one conductive layer is a pressure-sensitive conductive layer comprising a quantum tunnelling conductance (qtc) material. Contact between conductive layers is allowed during the absence of a mechanical interaction within said sensing zone. The sensor may be configured to provide a three-terminal sensing functionality or a four-terminal sensing functionality. The sensing zone may be substantially two-dimensional or substantially three-dimensional. The sensor may be substantially flexible or substantially rigid.