A foreign-object detecting device includes a first coil, a second coil arranged adjacent to the first coil and having the same winding direction as that of the first coil, and foreign-object detecting circuitry. The foreign-object detecting circuitry outputs a first detection signal to an outside or inside terminal of the first coil, outputs a second detection signal having an inverted phase to an outside or inside terminal of the second coil, causes one of the first and second detection signal to flow clockwise, causes the other detection signal to flow counterclockwise to generate a combined magnetic field across a center of the first and a center of the second coil, measures an amount of change in an impedance value of the first or second coils, and determines that a foreign object is present within the combined magnetic field, based on the amount of change.

The disclosure generally relates to methods, system and apparatus to detect a rogue object placed on an A4WP charging pad (interchangeably, charging mat). In one embodiment, presence of a rogue object on a charging pad is detected by measuring currents and voltages from sensor circuits on PTU and apply machine learning algorithms to develop power leakage algorithm. The algorithm identifies false objects placed on the charging pad and obviates false alarm while simultaneously detecting presence of a rogue object which can damage the A4WP wireless charging system.

The invention relates to a method for compensating a magnetic locator in the presence of a magnetic-field-disturbing material, comprising: an emitter (10) comprising at least one coil emitting an emission magnetic field; a receiver (20) comprising at least one receiving coil and a device providing a plurality of measurements Ip.sub.i of a receiving magnetic field induced by the emission field in each receiving coil; and a processing unit (25) comprising a field model allowing the calculation of a position (P) and/or an orientation (Q) of the receiver by means of calculation of a prediction H.sub.i of the measurements according to a criterion (C) calculated according to an error E.sub.i which is itself calculated in relation to the measurements Ip.sub.i. The invention is characterised in that the error E.sub.i is calculated by successive iterations from initial values prescribed by the prediction H.sub.i as being the difference between the measurements Ip.sub.i and a disturbed model Hp.sub.i, according to the equation E.sub.i=Ip.sub.i−Hp.sub.i, the disturbed model Hp.sub.i satisfying Hp.sub.i=H.sub.i+P.sub.i (α.sub.i=−arctan(βω.sub.i), (I) the parameter β being identical for all of the measurements Ip.sub.i, the calculation being carried out in such a way as to minimise the criterion C.

A fall-protection apparatus comprising at least one connector that comprises a resonant-frequency-shifting inductive sensing unit that is configured to detect whether the connector appears to be connected to a first item and is further configured to detect whether the connector appears to be connected to a second, different item.

A metal detector for detecting a target, the metal detector including: a transmitter for transmitting a transmitted magnetic field; a receiver, including a winding with a plurality of turns, for receiving a magnetic field; and a receive electronics connected to the winding for receiving signals from the winding. The receiver further includes an electrostatic screen covering at least part of the winding. The electrostatic screen is connected to an electronic circuit to receive signals from the receiver to reduce an effective capacitance presented by the electrostatic screen to the winding.

Systems and methods for sensing external magnetic fields in implantable medical devices are provided. One aspect of this disclosure relates to an apparatus for sensing magnetic fields. An apparatus embodiment includes a sensing circuit with at least one inductor having a magnetic core that saturates in the presence of a magnetic field having a prescribed flux density. The apparatus embodiment also includes an impedance measuring circuit connected to the sensing circuit. The impedance measuring circuit is adapted to measure impedance of the sensing circuit and to provide a signal when the impedance changes by a prescribed amount. According to an embodiment, the sensing circuit includes a resistor-inductor-capacitor (RLC) circuit. The impedance measuring circuit includes a transthoracic impedance measurement module (TIMM), according to an embodiment. Other aspects and embodiments are provided herein.

A method includes configuring a wireless power transfer system to operate in a sleep mode to reduce a quiescent current of the wireless power transfer system, configuring the wireless power transfer system to operate in a magnetic detection mode, wherein in the magnetic detection mode, an excitation is applied to a resonant tank of the wireless power transfer system, detecting a signal having a resonant attenuation envelope, wherein the signal is generated by the resonant tank, and configuring the wireless power transfer system to operate in an active mode after finding an object is magnetically coupled to the wireless power transfer system.

Systems and methods are described for extended foreign object detection (FOD) signal processing. In aspects, an oscillator reset is implemented in a FOD system to mitigate the effects of intermodulation products. In addition, dynamic frequency allocation is implemented to avoid high noise desensitizing the FOD system. Also, a slow sampling mode is implemented to increase a tolerance to transient foreign objects. Reference tracking and auto-recovery is implemented to bridge power outages. Additionally, the FOD system is configured to support position finding for determining an alignment between the vehicle pad and the base pad using a passive beacon transponder circuit and to perform beacon response cancellation as needed in concurrent FOD operation.

An electric composite detection antenna is disclosed. The antenna includes two RF antenna disposed on two sides of the circuit system of the electronic device, and a RF compensation system is disposed in the circuit system and includes an inductive sensing coil, and the induction coil can detect signal attenuation of any RF antenna subjected to external interference, so as to generate a detection signal. The RF compensation system can notice the control unit, to quickly drive any antenna matching circuit to switch to the RF antenna which is not interfered, or to quickly adjust antenna power or adjust the matching value of the RF antenna between the external environment, so that the preset electronic device can perform the stable transmission RF signal through the RF antenna without external interference, and maintain better power for RF signal transmissions.

The present teaching relates to method, system, medium, and implementations for detecting a target object via a security post. A plurality of sections are arranged in a vertical direction. Each section is designated to detect the target object in a vertical range by receiving information related to magnetic field from one or more sensors, analyzing the sensed information to extract features characterizing the magnetic field variations in the corresponding vertical range, and determining whether the target object is present in the vertical range based on the extracted features. When the target object is detected by a section, an alarm associated with the section is triggered to indicate the detection. An overall detection result is determined based on the detection result from each of the sections and is displayed on a display screen.