Described is a security sensor comprising two or more sub-sensors for use in a variety of installations where different magnetic fields may be experienced by the security sensor as a result of the variety of installations. One of the sub-sensors may have a low magnetic sensitivity while the other sub-sensor may have a much higher sensitivity to magnetic fields. In operation, one or both sub-sensors are used to determine if a door or a window has been opened.

A measurement apparatus is provided, which includes a magnetic sensor array formed by three-dimensionally arranging a plurality of magnetic sensor cells each including a magnetic sensor, and capable of detecting an input magnetic field in three axial directions; a measurement data acquiring section that acquires a plurality of measurement values based on the input magnetic field detected by the magnetic sensor array; a magnetic field calculating section that calculates the input magnetic field based on the measurement values; an error calculating section that calculates a detection error of the input magnetic field, based on the plurality of measurement values and a calculation result obtained by calculating the input magnetic field; and a measurement data selecting section that selects a plurality of measurement values to be used for calculating the input magnetic field by the magnetic field calculating section, from among the plurality of measurement values, based on the detection error.

The present invention relates to a hall electromotive force signal detection circuit and a current sensor thereof each of which is able to achieve excellent wide-band characteristics and fast response as well as high accuracy. A difference calculation circuit samples a component synchronous with a chopper clock generated by a chopper clock generation circuit, out of an output voltage signal of a signal amplifier circuit, at a timing obtained from the chopper clock, so as to detect the component. An integrating circuit integrates an output from the difference calculation circuit in the time domain. An output voltage signal from the integrating circuit is fed back to a signal amplifier circuit via a third transconductance element.

A tunneling magnetoresistance (TMR) sensor device is disclosed that includes four or more TMR resistors. The TMR sensor device comprises a first TMR resistor comprising a first TMR film, a second TMR resistor comprising a second TMR film different than the first TMR film, a third TMR resistor comprising the second TMR film, and a fourth TMR resistor comprising the first TMR film. The first, second, third, and fourth TMR resistors are disposed in the same plane. The first TMR film comprises a synthetic anti-ferromagnetic pinned layer having a magnetization direction of the reference layer orthogonal to a free layer. The second TMR film comprises a double synthetic anti-ferromagnetic pinned layer having a magnetization direction of the reference layer orthogonal to the magnetization of a free layer, but opposite to the magnetization direction of the reference layer of the first TMR film.

A magnetic sensor includes first to fourth resistor sections and a plurality of MR elements. Each of the plurality of MR elements belongs to any of first to fourth groups. The first to fourth groups are defined based on the areas of top surfaces of the MR elements. The first resistor section, the second resistor section, the third resistor section, and the fourth resistor section are constituted of the first group, the second group, the third group, and the fourth group, respectively; the second group, the first group, the fourth group, and the third group, respectively; the first group, the fourth group, the third group, and the second group, respectively; or the third group, the second group, the first group, and the fourth group, respectively.

According to one embodiment, a magnetic sensor includes a first conductive part circuit, an alternating current circuit part, a first direct current circuit part, and a first element. The first conductive part circuit includes a first conductive part including a first conductive part end portion and a first conductive part other-end portion, and a first alternating current transfer element electrically connected in series with the first conductive part. The first conductive part circuit includes a first circuit end portion and a first circuit other-end portion. The alternating current circuit part is configured to apply an alternating current voltage between the first circuit end portion and the first circuit other-end portion. The first direct current circuit part is configured to apply a first direct current voltage to the first conductive part end portion and the first conductive part other-end portion. The first element includes a first magnetic layer.

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.

A magnetic sensor may include a comparator to receive a first signal indicating a strength of a magnetic field sensed by a first sensing component of the magnetic sensor, receive a second signal indicating a strength of a magnetic field sensed by a second sensing component of the magnetic sensor, perform an error check associated with the first sensing component and the second sensing component, the error check being performed based on the first signal and the second signal, and provide an indication of a result of the error check. The magnetic sensor may include a protocol encoder to receive the first signal, receive the indication of the result of the error check, and provide an output that includes the indication of the result of the error check.

A frac dart including a pressure housing, a mechanically actuated magnetic sensor including a first magnet outside of the pressure housing, a signal generator inside the pressure housing and in operable communication with the first magnet, and an electrical counter disposed in the frac dart responsive in increments to the signal generator.

Described is a security sensor comprising two or more sub-sensors for use in a variety of installations where different magnetic fields may be experienced by the security sensor as a result of the variety of installations. One of the sub-sensors may have a low magnetic sensitivity while the other sub-sensor may have a much higher sensitivity to magnetic fields. In operation, one or both sub-sensors are used to determine if a door or a window has been opened.