Electromechanical watch capable of contactless communication with a communication device
AssigneeETA SA Manufacture Horlogere Suisse
InventorsLaurent Christe, François Klopfenstein, Joerg Berthoud
Life of this patent
Estimating the term…
Abstract
A watch (50) including an electromechanical movement provided with a stepper motor (2) and a control circuit (20) of the motor, and configured to communicate with an external communication device (100), including an antenna formed by the coil (18) of the motor and arranged to receive an amplitude-modulated magnetic signal according to the encoded data. The communication involves the generation of electrical detection pulses supplied to the coil of the motor with a pulse frequency corresponding to an encoding frequency of the magnetic signal.
Claims23
A timepiece (50) comprising an electromechanical movement provided with a stepper motor (2) and a control circuit (20) of the stepper motor, the stepper motor comprising a stator (4) defining two isthmi (12a, 12b) at a periphery of an opening (8) in the stator, a rotor (3) provided with a permanent magnet (6) located inside the opening, and a coil (18);
- the control circuit (20) being arranged so as to be able to generate electrical driving pulses to supply the coil and rotate the rotor;
- the timepiece comprising means for contactless communication with an external communication device, the communication means comprising an antenna formed by said coil of the motor and being arranged so as to be able to receive, from the external communication device, data encoded in bit form in a magnetic signal (70) formed by an external magnetic field (HExt) generated by the external communication device and amplitude-modulated such that a bit of value ‘0’ corresponds to an external magnetic field of weak or zero strength, defining a low level thereof, and such that a bit of value ‘1’ corresponds to an external magnetic field of relatively strong strength and defining a high level thereof, the communication means being arranged in such a way as to be able to decode the encoded data contained in said magnetic signal;
- wherein the communication means are arranged so as to be able to generate electrical detection pulses (82) supplied to the coil with a pulse frequency corresponding substantially to an encoding frequency of the magnetic signal;
- and wherein the communication means comprise a measurement circuit (32), arranged so as to be able to measure at least one parameter (TM) of each electrical detection pulse (82) of a plurality of electrical detection pulses generated by the communication means when receiving said encoded data in the magnetic signal, and a circuit (36) for processing said at least one parameter measured for each electrical detection pulse of said plurality of electrical detection pulses, said at least one parameter being selected and the processing circuit being arranged so as to allow the processing circuit to determine the high or low level of the external magnetic field (HExt) during an electrical detection pulse depending on said at least one parameter measured for the electrical detection pulse, so as to allow the processing circuit to determine the values of the bits of the encoded data contained in the magnetic signal.
A method for contactless communication between a timepiece (50) and an external communication device (100), the communication method comprising, in order for the timepiece to receive encoded data in bit form in a magnetic signal (70) transmitted by the external communication device, the following steps of:
- positioning the timepiece relative to the external communication device such that an external magnetic field (HExt) emitted by the device, to form the magnetic signal, propagates in the stator of the stepper motor mainly in a direction parallel to a general plane of the stator and substantially orthogonal to a direction (14) of alignment of the two isthmi (12a, 12b) of the stator;
- receiving, by the communication means of the timepiece, a signal for activating a communication mode;
- then
- generating at least one preliminary electrical pulse (84) supplied to the coil (18) of the stepper motor (2);
- and receiving, by the external communication device (100), at least one magnetic synchronisation pulse generated by said at least one preliminary electrical pulse circulating in the coil;
- detecting, using the external communication device, a specific time position in at least one magnetic synchronisation pulse of said at least one magnetic synchronisation pulse, a rising edge or a middle time value of at least one of the magnetic synchronisation pulses;
- then
- generating electrical detection pulses (82) supplied to the coil with a given pulse frequency and in phase with said at least one synchronisation pulse (84);
- and simultaneously transmitting the magnetic signal (70), using the external communication device, the encoded data having an encoding frequency substantially equal to the pulse frequency and the magnetic signal (70) being transmitted in such a way that the high and low levels of the external magnetic field (HExt), corresponding to the ‘1’ and ‘0’ bits of the encoded data, are synchronised with the electrical detection pulses (82) so that each high level of the external magnetic field, corresponding to a ‘1’ bit, is present in the stator (4) of the stepper motor during a corresponding detection pulse and so that each low level of the external magnetic field, corresponding to a ‘0’ bit, occurs during a corresponding detection pulse;
- measuring, using the detection circuit (24) of the communication means of the timepiece (50), said at least one parameter (TM) for each of the electrical detection pulses (82) occurring during the reception of said encoded data in the magnetic signal (70);
- processing, using the processing circuit (36) of said communication means, said at least one parameter measured for each electrical detection pulse (82) so as to determine, depending on said at least one parameter measured, whether the electrical detection pulse occurred during a high or low level of the external magnetic field and thus to determine the corresponding bit value, either ‘1’ or ‘0’, in the magnetic signal, so as to obtain a bit sequence corresponding to the encoded data in the magnetic signal.
Dependencies are inferred from the claim text.