A magnetic field monitor includes a magnetic field sensor that generates an electronic signal at a time period representing a magnetic field of the environment and includes a sensor transducer having a sensor bobbin, a primary coil, a secondary, over-winding coil, a sensor circuit, a controller connected to the primary coil, and a digitally controlled potentiometer connected to the secondary coil and controller. A non-linear output is converted to a quantitative linear output.

A magnetic field monitor includes a magnetic field sensor that generates an electronic signal at a time period representing a magnetic field of the environment and includes a sensor transducer having a sensor bobbin, a primary coil, a secondary, over-winding coil, a sensor circuit, a controller connected to the primary coil, and a digitally controlled potentiometer connected to the secondary coil and controller. A non-linear output is converted to a quantitative linear output.

An electromagnetic tracking system includes a hand held controller including an electromagnetic emitter configured to generate an electromagnetic field characterized by an electromagnetic field pattern and a first electromagnetic reflector positioned adjacent the electromagnetic emitter and configured to form a modified electromagnetic field pattern. The electromagnetic tracking system also includes a head mounted augmented reality display including an electromagnetic sensor configured to sense the electromagnetic field and a second electromagnetic reflector adjacent to sensor configured to optimally sense electromagnetic field pattern in a region of interest.

Provided is a magnetic detection device (100) having a simple configuration and being capable of stably detecting fine portions of a coin. The magnetic detection device (100) comprises an excitation coil (LX) that generates an alternating magnetic field in a transport path for transporting a coin in a first direction, and a plurality of detection coils (L1, L2) that are arranged at a predetermined pitch in a second direction and that output a detection signal based on an induction voltage caused by the alternating magnetic field. Each of the plurality of detection coils (L1, L2) outputs a detection signal on the basis of the induction voltage induced by the alternating magnetic field, which changes due to the coin being transported along the transportation path.

Systems, methods, apparatuses and non-transitory, computer-readable mediums are disclosed for short-range position tracking using a stationary magnetic field gradient. In an embodiment, a method comprises: obtaining, by a sensing array of a device worn or held by a user in an environment, a measurement of a stationary magnetic field generated by a magnetic source in the environment, the stationary magnetic field being independent of an ambient magnetic field in the environment; determining based on the measurement, a change in the magnetic field over time; determining based on the measurement, a change in the magnetic field over distance; obtaining, by the processor, a rotation angle of the device; determining a velocity of the device based on the change in the magnetic field over time, the change in the magnetic field over distance and the rotation angle of the device; and integrating the velocity to obtain a position of the device.

Systems, methods, apparatuses and non-transitory, computer-readable mediums are disclosed for short-range position tracking using a stationary magnetic field gradient. In an embodiment, a method comprises: obtaining, by a sensing array of a device worn or held by a user in an environment, a measurement of a stationary magnetic field generated by a magnetic source in the environment, the stationary magnetic field being independent of an ambient magnetic field in the environment; determining based on the measurement, a change in the magnetic field over time; determining based on the measurement, a change in the magnetic field over distance; obtaining, by the processor, a rotation angle of the device; determining a velocity of the device based on the change in the magnetic field over time, the change in the magnetic field over distance and the rotation angle of the device; and integrating the velocity to obtain a position of the device.

An electronic magnetometer and a method for measuring a magnetic field are provided. A Gunn diode with magnetic shielding and a Gunn diode without magnetic shielding generate different induced high-frequency oscillating currents in various environments. The high-frequency oscillating current of the Gunn diode with magnetic shielding and the high-frequency oscillating current of the Gunn diode without magnetic shielding are processed by circuits and subsequently compared. The difference of frequencies in the two currents is proportional to the magnitude of magnetic field, and the magnitude of magnetic field is obtained.

An electronic magnetometer and a method for measuring a magnetic field are provided. A Gunn diode with magnetic shielding and a Gunn diode without magnetic shielding generate different induced high-frequency oscillating currents in various environments. The high-frequency oscillating current of the Gunn diode with magnetic shielding and the high-frequency oscillating current of the Gunn diode without magnetic shielding are processed by circuits and subsequently compared. The difference of frequencies in the two currents is proportional to the magnitude of magnetic field, and the magnitude of magnetic field is obtained.

A current measurement circuit for determining a start time t.sub.START, an end time t.sub.END, and/or a peak time t.sub.MAX for a current pulse passing through a current conductor. The current measurement circuit includes a pickup coil and a threshold crossing detector. The pickup coil generates a voltage V.sub.SENSE proportional to a magnetic field around the conductor, which is proportional to a change in current over time. The threshold crossing detector compares V.sub.SENSE and a threshold voltage and generates an output signal indicative of a transition time and whether a slope of V.sub.SENSE is positive or negative. The current measurement circuit can also include an integrator and a sample and hold circuit. The integrator integrates V.sub.SENSE over time and generates an integrated signal V.sub.SENSE. The sample and hold circuit compares V.sub.SENSE to t.sub.MAX and generates a second output signal which can be used to measure the pulse current.

An article is provided having a substrate with an indicia printed on the substrate, where the indicia is printed with an ink that is detectable by in-line manufacturing production X-ray, metal, or magnetic detectors. A package for multiple such articles is also provided. A process for detecting a sanitizable substrate wipe with magnetic, metal, or X-ray detection equipment in a production setting is also provided. With process implementation article loss in a product can be detected thereby reducing precautionary product discard.