Patent ID: 7782175
Filing Date: 2010-08-24
Classification: H03K

Abstract:
1. A switch acting in contactless fashion for determining a distance between a first part and a second part, the switch comprising: a transceiver for attachment to one of the parts, the transceiver comprising a coil and being configured to receive power from an electrical supply source, wherein the amplitude of signals transmitted at the coil are affected by material located at the other of the parts; a transmission/reception circuit connected to the transceiver, the transmission/reception circuit being configured to: a first path comprising a proximity circuit connected for receiving the interrogation signal from the coil and to determine the distance between the parts based at least partly on an evaluation of the amplitude of the interrogation signal received from the coil; and a second path comprising: wherein the first and second paths are configured such that the transponder is identified at substantially the same time as the distance between the parts is determined.