Methods and apparatus for a sensor with a main coil to direct a magnetic field at a rotating target for inducing eddy currents in an end of the target and a sensing element to detect a magnetic field reflected from the target, wherein the target end comprises a conductive surface. The reflected magnetic field can be processed to determine an angular position of the target.

An activity classification device is disclosed. The activity classification device comprises one or more motion sensors and a memory configured to receive signals from the one or more motion sensors. The device further includes a processor in communication with the memory. Finally, the device includes a classification algorithm executed by the processor, the classification algorithm for identifying activities that a user is engaged in. The memory may also record a user's activity log, calorie count and an RF module, which transmits the recorded data to a host either upon request or continuously.

An activity classification device is disclosed. The activity classification device comprises one or more motion sensors and a memory configured to receive signals from the one or more motion sensors. The device further includes a processor in communication with the memory. Finally, the device includes a classification algorithm executed by the processor, the classification algorithm for identifying activities that a user is engaged in. The memory may also record a user's activity log, calorie count and an RF module, which transmits the recorded data to a host either upon request or continuously.

A device for measuring disruptions in a controlled magnetic field and generated by the device itself surrounding a sole conductive element, antenna or electrode and comprising, at least: a controlled magnetic field sensor comprising, in turn, an oscillator circuit connected to at least one electrode, a digital module; and a processor connected to the digital module. The applications of the device that is the object of the invention are all those requiring the detection of an object prior to it resulting in the violation of the restricted space. Amongst these applications we can highlight the following: the localisation of people, industrial security applications, robotics, domestic security applications, military applications and vehicle security applications.

The present invention provides a triaxial magnetism detecting apparatus having a high mechanical strength and being compact in size by simplifying the arrangement configuration of magnetism detectors for the reduction of the number of components and allowing easy angular adjustment of the magnetism detectors and easy installation of the magnetism detectors on the apparatus body, and a satellite. A triaxial magnetism detecting apparatus has a power supply board, a circuit board, and a magnetism detecting unit, which are fixed on a body, and the circuit board and the magnetism detecting unit are horizontally connected. By using the magnetism detecting unit, the triaxial magnetism detecting apparatus detects magnitudes of magnetic fields in mutually perpendicular X-axis, Y-axis, and Z-axis directions.

One embodiment is a magnetic field measurement system that includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes at least one feedback loop that includes a first low pass filter with a first cutoff frequency. The feedback circuit is configured to compensate for magnetic field variations having a frequency lower than the first cutoff frequency. The first low pass filter rejects magnetic field variations having a frequency higher than the first cutoff frequency and provides the rejected magnetic field variations for measurement as an output of the feedback circuit.

One embodiment is a magnetic field measurement system that includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes at least one feedback loop that includes a first low pass filter with a first cutoff frequency. The feedback circuit is configured to compensate for magnetic field variations having a frequency lower than the first cutoff frequency. The first low pass filter rejects magnetic field variations having a frequency higher than the first cutoff frequency and provides the rejected magnetic field variations for measurement as an output of the feedback circuit.

A calibration device comprising: a plurality of magnetic sensors positioned at the calibration device, the plurality of magnetic sensors defining a space; a controller configured to be positioned in the space defined by the plurality of magnetic sensors, wherein the controller includes a magnetic transmitter; and one or more processors configured to: cause the magnetic transmitter to generate magnetic fields; receive signals from the plurality of magnetic sensors that are based on characteristics of the magnetic fields received at the plurality of magnetic sensors; calculate, based on the signals received from the plurality of magnetic sensors, positions and orientations of the plurality of magnetic sensors relative to a position and orientation of the magnetic transmitter; and determine whether the calculated positions and orientations of the plurality of magnetic sensors are within one or more threshold limits of known positions and orientations of the plurality of magnetic sensors.

A sensor die may include a set of sensing elements and a test structure associated with determining a magnetic sensitivity of the set of sensing elements. The test structure includes a first test sensing element sensitive in a direction in a plane defined by a surface of the sensor die, a second test sensing element sensitive in the direction in the plane defined by the surface of the sensor die, and a wire on chip (WoC) associated with applying a magnetic field to the first test sensing element and the second test sensing element. The first test sensing element, the second test sensing element, and the WoC may be arranged such that, when current flows through the WoC, the first test sensing element senses a component of the magnetic field in the direction, and the second test sensing element senses a component of the magnetic field in a perpendicular direction.

The present invention relates to a system for monitoring an electromechanical relay, wherein the electromechanical relay includes a relay coil for actuating at least one switch, the system comprising: at least one sensor adapted to measure an operating condition of the electromechanical relay, wherein the sensor is arranged adjacent or attached to the electromechanical relay; at least one controller communicatively connected to the at least one sensor and at least one memory, wherein the at least one controller is adapted to store the measured operating condition in the at least one memory; at least one transmitter, operatively connected to the controller, wherein the transmitter is adapted to transmit the stored measured operating condition to a remote device.