A system for magnetic field testing comprising a magnetic field generation device configured to generate a magnetic field in a rotor, a plurality of magnetic field measurement devices configured to measure a magnetic field at a predetermined position on the rotor, a drive mechanism configured to rotate the rotor and a test system configured to record the plurality of magnetic field measurements as a function of an angular position of the rotor.

A method includes receiving a signal that is generated at least in part by one or more magnetic field sensing elements in response to a magnetic field associated with a rotating target, the rotating target a changing feature that changes with target rotation angle, the one or more magnetic field sensing elements being part of a sensor; detecting a current value of the signal; and identifying a current angular position of the rotating target relative to the sensor based on: (i) the current value of the signal and (ii) a map that maps each of a plurality of values of the signal to a different respective angular position of the rotating target.

A stroke sensor includes: a shaft that extends in an axial line direction; a detected body that is fixed to the shaft; a housing that extends along the shaft, that houses the shaft, and that supports the shaft slidably in the axial line direction; and a detection body that detects a movement amount of the detected body which moves in accordance with sliding of the shaft, wherein the shaft includes a plurality of shaft members that are connected to each other in the axial line direction and that are formed of metal, and a slide part that is in contact with an inner wall of the housing and that slides so as to regulate a movement of the shaft in a direction that is crossed with the axial line is provided on each of the plurality of shaft members.

A power tool includes a case, a motor, a plurality of Hall effect sensors, a first circuit board, and a second circuit board. The Hall effect sensors detect a position of a rotor of the motor and correspondingly generate position signals. A plurality of commutating switches and a first controller are disposed on the first circuit board. A second controller is disposed on the second circuit board, and could transmit a driving signal to the first controller according to the operating signal of an operator interface. The first controller regulates the commutating switches to commutate according to the driving signal and the position signals, thereby to activate the rotor to rotate. With such design, a commutation process and a user operating process are regulated by the two different controllers, which could efficiently simplify the program code installed in each of the controllers and facilitate the maintenance of the controllers.

Disclosed is linear displacement absolute position encoder used for measuring displacement of a tested apparatus. The linear displacement absolute position encoder comprises a base, a magnetoresistive sensor array, an encoding strip, and a back magnet. The encoding strip is fixed on the base and extends in the direction of a rail of the tested apparatus. The encoding strip is a magnetic material block having recess and protrusion for identifying encoding information of different positions. The magnetoresistive sensor array is arranged between the encoding strip and the back magnet in a non-contact manner. The back magnet is used for generating a non-uniform magnetic field around the encoding strip so as to magnetize the encoding strip. The magnetoresistive sensor array is used for acquiring the position encoding information of the encoding strip by detecting magnetic field information of the encoding strip. The encoder is low cost and can monitor large distances.

A rotational position sensor arrangement having first and second sensors positioned adjacent to first and second axial faces or a first axial face and a radial face of a target disc. The target disc has first and second wave profiles on the first axial face and the second axial or radial face, having respectively, first and second pluralities of segments, with each segment being formed with axially offset peaks and valleys which extend along radial lines/planes. The valleys separate the segments, and the number of the first plurality of segments is different than that of the second plurality of segments. The first and second sensors signal a controller with data on a field variance due to a difference in at least one of a size or location of the first and second wave profiles as they pass the first and second sensors to determine a rotational speed and/or position.

Systems and methods for determining angular position in rotating machines. A repeating sequence of segments are arranged in a track disposed at a diameter around a shaft of a rotor that rotates about an axis. A sensor is positioned to face the track and is fixed relative to the stator. The track and the sensor face to each other, which may be in directions that are parallel to the axis. The sensor generates an output that is decoupled from the diameter of the track and is related to the repeating sequence of segments.

Magnetic sensor arrangement comprising a component board delimited by two opposing main surfaces and having an accommodation hole for accommodating at least part of a magnetic field generating structure, and a magnetic sensor package located at least partially between the two opposing main surfaces and configured for sensing a magnetic field generated by the magnetic field generating structure.

A magnetic field measuring device having a semiconductor body with a first surface running in an x-y plane, with a first and second magnetic field sensor disposed on the surface, and an axis of symmetry, which runs perpendicular to the first surface in the z-direction and to which the magnetic field sensors are positioned in a mirrored fashion, first and second magnets, which are spaced apart from one another and in each case have an axis and a polar surface running perpendicular to the axis and facing the semiconductor body. The magnetic polarity changes along the axes on a surface, whereby the axes run in the direction of the axis of symmetry, whereby the axis of symmetry runs between the axes of the magnets, whereby the surfaces of the magnets in each case are spaced apart in the z-direction to the first surface of the semiconductor body.

One embodiment provides a method, including: detecting, using a sensor of an information handling device, a change in a magnetic field associated with the information handling device; determining, using a processor, whether the change in the magnetic field corresponds to a known command; and performing, responsive to determining that the change in the magnetic field corresponds to the known command, a function dictated by the known command. Other aspects are described and claimed.