Patent ID: 8664942

Claim:
A sensor device for a height measurement, comprising: a transceiving coil arrangement including at least one transceiving coil; a transmitting drive unit; a receiver unit; a reference coil arrangement; and a reference control unit, wherein the transceiving coil arrangement is coupled to both the transmitting drive circuit and the receiver unit, wherein the reference control unit is coupled to the reference coil arrangement, wherein the reference coil arrangement is movably positioned with respect to the transceiving coil arrangement, wherein the drive unit is adapted to drive the transceiving coil arrangement with an AC power signal of a predetermined duration for generating a magnetic field, wherein the reference control unit is adapted for accumulating energy out of the generated magnetic field and for generating a reference signal based on an amount of the accumulated energy, and wherein the receiver unit is adapted for receiving the reference signal and for outputting a signal for determining a distance between the transceiving coil arrangement and the reference coil arrangement based on at least one out of a group, the group consisting of the reference signal and the duration of the AC power signal.