Identifying system for identifying a medical tool like a surgical instrument

An identifying system for identifying a passive medical identification device,

• wherein the passive medical identification device comprises,
• a casing, a magnetic object being arranged within the casing such that it is rotatable out of an equilibrium orientation if an external magnetic torque is acting on the magnetic object,
• a restoring torque provider being configured to provide a restoring torque to force the magnetic object back into the equilibrium orientation if an external magnetic torque has rotated the magnetic object out of the equilibrium orientation, in order to allow for a rotational oscillation of the magnetic object excited by the external magnetic torque, the rotational oscillation generating a response magnetic signal, the casing, magnetic object and the restoring torque provider being arranged such that at least one property of the response magnetic signal is suitable to be used by an identification system to extract identification data from an induction signal.
• wherein the identifying system comprises:
• an excitation and induction signal coil system configured to:
• a) generate a magnetic field providing a magnetic torque for rotating the magnetic object of the identification device out of its equilibrium orientation and for thereby exciting a rotational oscillation of the magnetic object, the rotational oscillation inducing a response magnetic field, and
• b) transduce the response magnetic field into an induction signal,
• and comprising a processor configured to receive the induction signal and to extract identification data.