A portable meter (1) for measuring a force generated by a magnetic apparatus (2), comprising a mobile probe (3) configured to be coupled to the magnetic apparatus (2) whose force needs to be measured, the probe (3) comprising at least one active ferromagnetic element (4) which has a configuration corresponding to that of a pole (N, S) on the magnetic apparatus whose force needs to be measured, the probe being equipped with alignment means (5, 6) configured to align the at least one active ferromagnetic element (4) with at least one magnetic pole (N, S) on the magnetic apparatus (2), the at least one active ferromagnetic element (4) having at least one turn (B)—made of an electrically conductive material—wound around it, and a detection unit (7) interfaced with the at least one turn (B) in order to detect a magnetic flux flowing through the coil at least during a transient of activation/deactivation of the magnetic apparatus.

A system and method of effectively measuring a change in a gradient of a magnetic field. The systems include a first magnet and a second magnet mechanically coupled together and aligned along a polarization axis. The first magnet and the second magnet are positioned such that a pair of like magnetic poles of the first magnet and the second magnet face in opposite directions. Further, the first magnet and the second magnet are configured to move along the polarization axis in response to a magnetic field. A sensing system is configured to measure a change in a gradient of the magnetic field based on the movement of the first magnet and second magnet along the polarization axis in response to the magnetic field.

A method for measuring a magnetic field with a micro-sensor system includes applying a direct current (I.sub.Th) to a curved micro-beam to control a stiffness of the curved micro-beam; placing the micro-sensor system into an external magnetic field (B); selecting with a controller, based on an expected value of the external magnetic field (B), a given resonant frequency of the micro-beam; measuring with a resonant frequency tracking device the given resonant frequency of the micro-beam; and calculating in the controller the external magnetic field (B), based on (1) the measured resonant frequency, (2) the applied current (I.sub.Th), and (3) calibration data stored in the controller. The calibration data is indicative of a dependency between a change of the selected resonant frequency and the external magnetic field.

A gradiometer includes a at least one magnet attached to a beam. The magnet moves in response to a magnetic force. A sensing element is configured to measure movement or deflection of the beam or magnet. The gradiometer is configured to determine a gradient of a magnetic field acting on the first magnet based on movement of the magnet. The gradiometer can further measure higher order gradients.

A magnetic distribution detection method includes the steps of providing a magnetic sensor and a sample, selecting a multiple of measuring points on the sample, sensing the measuring points by the magnetic sensor, obtaining a multiple of sense data and a series of the heights of the magnetic sensor from each measuring point, using a signal decomposition algorithm to convert these sense data into data groups, and selecting one of the data groups as the magnetic distribution data of the sample.

A transducer assembly includes an engagement plate, a mounting plate, a support structure, and first and second Hall effect sensor assemblies. The mounting plate defines an S-shaped cutout extending through the mounting plate to define first and second finger regions and a perimeter region. The first finger region includes a first distal end spaced from the perimeter region by a first gap defined by the S-shaped cutout. The second finger region includes a second distal end spaced from the perimeter region by a second gap defined by the S-shaped cutout. The support structure includes a base and first and second tabs. The base is sandwiched between the engagement plate and the mounting plate. The first and second tabs extend from the base and into the first and second gaps, respectively. The first and second Hall effect sensor assemblies are configured to detect movement of the first and second tabs, respectively.

A gradiometer includes a at least one magnet attached to a beam. The magnet moves in response to a magnetic force. A sensing element is configured to measure movement or deflection of the beam or magnet. The gradiometer is configured to determine a gradient of a magnetic field acting on the first magnet based on movement of the magnet. The gradiometer can further measure higher order gradients.

The present invention relates to a magnetic controlled Bluetooth device and more particularly to a magnetic controlled Bluetooth speaker. The magnetic controlled Bluetooth device comprises a magnetic unit and a magnetic sensor. As another magnetic unit approaches the magnetic sensor of the magnetic controlled Bluetooth device, the magnetic sensor varies its output voltage in response to the magnetic field of another magnet. Thus, the magnetic controlled Bluetooth device can be turned on to execute a Bluetooth pairing process. Further, the magnetic unit of the magnetic controlled Bluetooth device can be used to approaches another magnetic sensor of another magnetic controlled Bluetooth device to turn on another magnetic controlled Bluetooth device.

A system for estimating flux linkage in an electric motor includes a flux estimation module that generates estimated flux linkages based on a back electromagnetic force and estimated velocity of the electric motor, the flux linkages having an alpha flux linkage component and a beta flux linkage component, and a velocity estimation module that generates an estimated motor velocity based on the back electromagnetic force and the estimated flux linkages.

A device for detecting an object is suggested comprising a magnetic field sensor, a magnet that is arranged to rotate in a vicinity of the magnetic field sensor, wherein the object is movable in the vicinity of the magnet to affect the rotation of the magnet, wherein the magnetic field sensor is arranged to detect a magnetic field of the magnet. Also, a system comprising such device is provided.