Showing papers on "Inductive sensor published in 2013"

Electronic Device With Shared Near Field Communications and Sensor Structures

Abstract: An electronic device may have electrical components such as sensors. A sensor may have sensor circuitry that gathers sensor data using a conductive structure. The sensor may be a touch sensor that uses the conductive structure to form a capacitive touch sensor electrode or may be a fingerprint sensor that uses the conductive structure with a fingerprint electrode array to handle fingerprint sensor signals. Near field communications circuitry may be included in an electronic device. When operated in a sensor mode, the sensor circuitry may use the conductive structure to gather a fingerprint or other sensor data. When operated in near field communications mode, the near field communications circuitry can use the conductive structure to transmit and receive capacitively coupled or inductively coupled near field communications signals. A fingerprint sensor may have optical structures that communicate with external equipment.

Capacitive body proximity sensor system

Abstract: Described herein are systems, methods and apparatuses that can detect the proximity of an object and differentiate between a human body and a non-human object. The detection and differentiation are facilitated by a first capacitive sensor of a first shape and a second capacitive sensor of a second shape. The detection and determination can be made based on a comparison between a first capacitance from the first sensor and a second capacitance from the second sensor.

Novel Optimization Algorithm to Demodulate a PZT-FBG Sensor in AC High Voltage Measurements

Abstract: The application of optical fiber sensors in high-voltage environments has long been recognized as being useful, due to many properties of silica, such as insulation and electromagnetic induction immunity. Thus, optical voltage transducers offer many improvements on traditional inductive and capacitive voltage transformers, such as linear performance, wider dynamic range, lighter weight, smaller size, and improved safety. In this paper, we aim toward a power-line voltage transformer application by using a piezoelectric ceramic crystal stack together with a fiber Bragg grating (FBG) sensor to construct the core of a potential transformer for 13.8 kV class. For the AC demodulation process, we develop a mathematical model to identify the optimization parameters through a novel algorithm to improve sensitivity on FBG demodulation. This new scheme is simple, reduces the cost of the setup implementation and shows a solution to circumvent the temperature drift of the system.

System and method for measuring variable impedance elements in a wireless sensor

Abstract: A wireless remote sensor (110) that is powered by an inductive transmitter (112) and is configured to produce an oscillating wave that varies based on one or more sensed parameters. The oscillating wave is communicated to the inductive transmitter (112) by reflected impedance, where it can be detected to determine the sensed value(s). In another aspect, the present invention provides a wireless remote sensor with a Wheatstone bridge arrangement having an internal resonant circuit to produce an electromagnetic field indicative of the sensed value. In a third aspect, the present invention provides a wireless remote sensor with optical feedback from a reference circuit and a sensor circuit. In a fourth aspect, the present invention provides a wireless remote temperature sensor having coils printed on a material with a high coefficient of thermal expansion so that the size and/or shape of the coils varies as the temperature increases or decreases.

Characterization of Magnetic Immunity of an Ironless Inductive Position Sensor

Abstract: The ironless inductive position sensor is a novel linear position-sensing device that should exhibit immunity to external magnetic fields while simultaneously guaranteeing high-precision measurements in harsh environments. This paper focuses on the characterization of the sensor's working principle and magnetic field immunity. The sensor is tested, with both voltage and current supply, with different dc and slowly varying magnetic field patterns in order to prove its immunity and analyze the differences and similarities between the two supply cases. The measurements are performed with a test bench on a custom prototype, which is especially manufactured for this purpose.

Nanoscale displacement sensing using microfabricated variable-inductance planar coils

Abstract: Microfabricated spiral inductors were employed for nanoscale displacement detection, suitable for use in implantable pressure sensor applications. We developed a variable inductor sensor consisting of two coaxially positioned planar coils connected in series to a measurement circuit. The devices were characterized by varying the air gap between the coils hence changing the inductance, while a Colpitts oscillator readout was used to obtain corresponding frequencies. Our approach shows significant advantages over existing methodologies combining a displacement resolution of 17 nm and low hysteresis (0.15%) in a 1 × 1 mm2 device. We show that resolution could be further improved by shrinking the device's lateral dimensions.

Radio frequency current-voltage probe for impedance and power measurements in multi-frequency unmatched loads.

Abstract: A broad-band, inline current-voltage probe, with a characteristic impedance of 50 Ω, is presented for the measurement of voltage and current waveforms, impedance, and power in rf systems. The probe, which uses capacitive and inductive sensors to determine the voltage and current, respectively, can be used for the measurement of single or multi-frequency signals into both matched and unmatched loads, over a frequency range of about 1–100 MHz. The probe calibration and impedance/power measurement technique are described in detail, and the calibrated probe results are compared with those obtained from a vector network analyzer and other commercial power meters. Use of the probe is demonstrated with the measurement of power into an unmatched capacitively coupled plasma excited by multi-frequency tailored voltage waveforms.

Infrared Sensors for Electronic Devices

Abstract: An electronic device may be provided with proximity sensor capabilities for monitoring for the presence of nearby external objects. The electronic device may make temperature measurements such as measurements involving the monitoring of nearby objects for emitted blackbody light indicative of whether or not the external object is a heat-emitting object such as a human body part. The same sensor that is used in gathering temperature readings may be used in gathering proximity sensor data or separate temperature sensor and proximity sensor detector structures may be used. Motion sensor capabilities may be provided using sensor structures having an array of heat sensing elements. Signals from the array of heat sensing elements may be used in making temperature measurements and in gathering proximity sensor readings. Sensor structures may operate at wavelengths longer than 3 microns such as wavelengths from 3-5 microns or 10-15 microns.

Development of a proximity sensor with vertically monolithic integrated inductive and capacitive sensing units

Abstract: This study designs and implements a proximity sensor consisting of inductive and capacitive sensing units. These two sensing units are vertically monolithic integrated on a single chip using the micro-fabrication processes. In addition, low-temperature fabricated nanoporous anodic aluminum oxide (np-AAO) is employed as the dielectric layer to enhance the performance of capacitive sensing. The characteristics of the presented vertically monolithic integrated inductive and capacitive proximity sensor are as follows: (1) enlarged sensing distance of conductive objectives: capacitive sensing unit for short distance detection and inductive sensing unit for long distance detection, (2) non-conductive object can be detected by the capacitive sensing unit, (3) fringe effect capacitive sensing is enhanced by the spiral coil electrode and (4) np-AAO has good dielectric properties (the dielectric constant is 11.9 in this study) for capacitive sensing. In application, various materials (including metal, plastic and a human finger) have been successfully detected by the presented sensor. Preliminary results demonstrate that the typical fabricated proximity sensor has a sensing range of 0.5–5 mm for the metal rod. In comparison, the inductive and capacitive sensing units have the sensing ranges of 1.5–5 and 0.5–3 mm, respectively. Moreover, the non-conductive plastic rod can be detected by the capacitive sensing unit.

The Self-Excitation Phenomenon of Quasi Shielded Inductive Proximity Switches

Abstract: Authors of this article had to build the Poka-Yoke [ unit for unusual geometry element, which require to use the inductive proximity switches with relatively small diameter and good sensing range. Industrial sensors suppliers putted on to the market new type of sensor named quasi flush or semi flush which fulfill the needs. An article shows the observed influence of the geometry of tested elements for the self-excitation phenomenon of quasi shielded inductive proximity switches. In consequence this phenomenon can cause in false quality control and passing the wrong elements through the Poka-Yoke unit.

Proximity sensing using driven ground plane

Abstract: A method and apparatus for operating an input device having an array of capacitive sensor electrodes disposed on a substrate with a ground plane, and a proximity sensor electrode are disclosed herein. The input device includes a processing system configured to operate in an input mode and a proximity mode. When operating in the input mode, the processing system drives the ground plane to a grounding voltage and scans the array of capacitive sensor electrodes to detect input from an object in an active region of the input device. When operating in the proximity mode, the processing system drives a sensing signal on the ground plane, and optionally, one or more sensor electrodes of the array of capacitive sensor electrodes and receives a resulting signal from the proximity sensor electrode. The processing system generates an indication of an object presence in a second sensing region based on the resulting signal.

Modeling of High-Frequency Electromagnetic Effects on an Ironless Inductive Position Sensor

Abstract: The ironless inductive position sensor (I2PS) is a five-coil air-cored structure that senses the variation of flux linkage between supply and sense coils and relates it to the linear position of a moving coil. In air-cored structures, the skin and proximity effect can bring substantial variations of the electrical resistance, leading to important deviations from the low-frequency functioning. In this paper, an analysis of the effect of high-frequency phenomena on the I2PS functioning is described. The key-element is the modeling of the resistance as a function of the frequency, which starts from the analytical resolution of Maxwell's equations in the coil's geometry. The analysis is validated by means of experimental measurements on custom sensor coils. The resulting model is integrated with the existing low-frequency analysis and represents a complete tool for the design of an I2PS sensor, framing its electromagnetic behavior.

Design of Highly Selective Metamaterials for Sensing Platforms

Abstract: This paper presents a methodology to construct novel label-free sensing platforms using carefully engineered materials (metamaterials) that have dimensions considerably smaller than the operating wavelength, λ. This paper demonstrates that highly selective sensing platforms can be achieved by using metamaterials consisting of periodic arrays of capacitive and inductive elements. Specifically, this paper gives the design of the following four basic sensing parameters of sensing platforms: 1) resonant frequency ω0; 2) resonant frequency shift Δω0; 3) bandwidth B; and 4) transmission ratio T. Using this approach, the bandwidth B and resonant frequency ω0 can easily be modulated by using different combination sets of metallic patch elements and metallic wire elements. Equivalent circuit analysis and numerical methods have been applied to determine the basic sensing design rules for constructing periodic arrays of capacitive and inductive elements, and the efficiency of the obtained label-free sensing architectures has been evaluated. The overall contribution of this paper is to develop a methodology for designing highly selective biosensors by optimizing the dimensions of underlying circuit at the subwavelength scale.

Inductive sensor for angular measurement of the position of a moving part and measuring method using such a sensor

Abstract: An inductive sensor includes a primary winding, two secondary windings and a moveable target, the primary winding being centered about a central axis and carrying a high-frequency alternating current which can induce a voltage in secondary windings, the secondary windings also being centered about the central axis and made up of a number k of substantially identical loops, which are successively crossed and arranged opposite the primary winding. In this case, the target is made up of a part having p=1 angular sector with an angular opening. The opening of the angular sector of the target is less than that of a loop of secondary winding with a deviation calculated such as to eliminate the fourth harmonic of the linearity deviation Fourier decomposition, between the measured angular value and real angular value for the position of the target over the measurement course.

Systems and methods for offset reduction in sensor devices and systems

Abstract: Embodiments relate to systems and methods for reducing errors in sensor devices and systems. In embodiments, the sensor devices comprise magnetic field sensor devices, such as ordinary or vertical Hall sensor devices, and the error to be reduced is a residual offset error, though in other embodiments other sensor devices can be used and/or other types of errors can be targeted for reduction or elimination. In one embodiment, at least two such sensor devices not electrically coupled with one another are sequentially operated in a spinning current-type mode such that an individual output signal from each of the at least two sensor devices is obtained. A total output signal can then be calculated, such as by averaging or otherwise combining the individual output signals from each sensor device.

Inductive touch sensor using a flexible coil

Abstract: An inductive touch sensor comprises an inductors disposed in or on a deformable substrate. When a force is applied to the deformable substrate the physical shape of the inductor will change and thereby change its inductance value. The change in the inductance value can be detected and used to indicate actuation of an associated touch key of the inductive touch sensor. A plurality of inductive touch sensors may be used to form a touch panel.

Sensor and sensing method

Abstract: A sensor is provided, which may include: a sensor layer containing a sensor material, wherein an electrical resistance of the sensor material changes upon adsorption of an adsorbate at the sensor material; a circuit electrically coupled to the sensor layer and configured to apply an electrical current to the sensor layer that heats the sensor layer.

Determining forces of contacts between styluses and objects

Abstract: An apparatus comprising a stylus with a dynamically switch tip shield is provided The apparatus includes an elongated stylus housing having an end, a conductive tip disposed at least partially inside the stylus housing and extending from the end, a force sensor coupled to the conductive tip and configured to detect contact between the conductive tip and an object, a tip shield coupled with the stylus housing and extending from the end, and a switch coupled to the tip shield and the conductive tip The force sensor may be an inductive sensor, a capacitive sensor, a piezo sensor, a force sensing resistor sensor, or an optical sensor

A simple signal conditioning scheme for inductive sensors

Abstract: Signal conditioning of inductive sensors so as to obtain an output proportional to just the change in the inductance alone is fraught with problems. The large value of self inductance that is present in a sensor coil and the change in the inductance being a small fraction of this large inductance coupled with the winding resistance of the sensor coil make signal conditioning of such inductive sensors a challenge. This paper presents a simple analog front-end suitable for signal conditioning of inductive sensors. The proposed signal conditioning circuit provides an output linearly related to the change in inductance due to the measurand alone, masking the large value of self (offset) inductance present in inductive sensors as well as the appreciable winding resistance. A prototype of the proposed signal conditioning circuit was developed and tested in the laboratory. Test results validate the efficacy of the technique presented herein.

Capacitive proximity sensor configuration including an antenna ground plane

Abstract: Embodiments of a capacitive sensor configuration for proximity detection by a playback device are provided. The playback device may include a capacitive proximity sensor configured to detect physical movement in a first direction, and a radio frequency (RF) antenna ground plane oriented at a relative angle to the capacitive proximity sensor. The capacitive proximity sensor may include a first metal electrode coupled to the RF antenna ground plane is coupled to the first metal electrode such that the capacitive proximity sensor may be further configured to detect physical movement in a second direction that is substantially the relative angle to the first direction. The playback device may be configured to determine based on a detection of physical movement by the capacitive proximity sensor, a physical approach of an entity towards the playback device from one or more of the first direction and the second direction.

Capacitive sensor for an anti-collision apparatus

Abstract: A capacitive sensor detects an object, in particular detects a collision in the case of a movable vehicle part. The sensor has an electrode arrangement which contains at least one sensor electrode. The sensor also has an evaluation circuit which is connected downstream of the sensor electrode and is intended to process a reception signal generated in the sensor electrode. In this case, the evaluation circuit contains a transimpedance amplifier which has a device for compensating for the frequency response.

Inductive sensor with demodulator

Abstract: A transconductor converts voltage on an inductive sensor to a proportional current using two “coupling” capacitors. Responsive to movement of an electrically conductive target from the null position a resonant current is formed between the two sensor coils. A single differential transistor pair switched by periodic drive signals commutes the net alternating current at the single input to direct current.

A new eddy current sensor composed of three circumferential gradient winding coils

Abstract: This paper proposes a new eddy current testing sensor composed of three planar fan-shaped circumferential gradient winding spiral coils. We study the crack detection principle by using the ECT sensor. The experiment of crack detection is set up and a series of samples machined with a slot at different size are detected by using the ECT sensor. Finally the quantitative estimations of crack width, depth and extension direction are studied, which prove the method is feasible and reliable.

Multi-Frequency Dielectric Borehole Imager

Abstract: Systems, methods and devices for dielectric borehole imagery are disclosed. Systems may include one or more transmitters that induce, at azimuthally-spaced positions on a borehole wall, a plurality of fields having components in non-coplanar directions within a formation; one or more directionally sensitive receivers that sense the components caused by each of the one or more transmitters; and a controller that processes signals received from the one or more directionally sensitive inductive sensors to provide a set of measurements representative of dielectric parameters at two or more azimuthal positions within the borehole.

A new inductive proximity sensor as a guiding tool for removing metal shrapnel during surgery

Abstract: In this paper, an inductive proximity sensor with a longer range when compared to its diameter is presented. This sensor is intended to guide doctors, while performing surgery to remove metal shrapnel from victims of bomb blasts, gun fire, land mines etc. Presently doctors rely on imaging systems to locate shrapnel in the victim's body before surgery. Effectiveness of surgery and recovery solely depends on the doctors' skill to trace the shrapnel. In some cases the shrapnel may be visible in the images, but it may be untraceable during surgery. So in such cases, an inductive proximity sensor which is small enough to be introduced into the victim's body and can direct the recovery tool effectively to the exact location of the shrapnel, during the surgery, will be very useful to the doctor. Such a sensor, along with its details and experimental results are presented in this paper. This sensor works on a new comparison based method to detect tiny targets, as the detector size is a constraint here. The sensor can detect shrapnel materials such as steel, brass and Aluminium. A smaller, modified version of this sensor is also presented in the paper, along with a study of the effect of body tissues on sensor performance.

Inductive sensor device and inductive proximity sensor with an inductive sensor device

Abstract: An inductive sensor device for detecting a magnetic field change caused by an object approaching in the region of an influencing side of the inductive sensor device includes at least one coil system having a transmitting coil fed with alternating current and first and second receiving coils. The two receiving coils are connected in series in opposite senses, the first receiving coil is disposed in front of the transmitting coil and the second receiving coil is disposed behind the transmitting coil, relative to the influencing side. A screen is provided behind the second receiving coil relative to the influencing side. An inductive proximity sensor with an inductive sensor device is also provided.

The Influence of Diagnostic Signal Measurement Period on Blades Technical Condition Images Determined from Phase Shift Difference

Abstract: In the article, new method of monitoring of rotor machine blades technical condition is presented. This method is based on diagnostic model φT12T01 [ which uses phase shift difference of signal fragments resulting from blade operation y (t) during blade recession from sensor and during approach of blade tip towards the sensor as well as signal of its environment x (t) described using proper distribution. The assumed diagnostic model also indirectly includes actual blade environment x (t) without necessity of its measurement [3,. Contactless inductive sensor constantly measures the signal of operating blade transition below the sensor. However, several difficulties with determination of last sample of blade receding from the sensor with first sample of blade approaching the sensor exist. Additionally the problem occurs with measurement of space between blades. So far, the case was solved by use 90% of this space range (in order to eliminate the overlapping of adjacent blades signals). Hence the problem of assessment of measurement period breadth on obtained models (images) of blades. The possibility of blade damage detection by analysis of less than 90% signal course was tested.

Steering wheel steering angle sensor device

Abstract: The invention discloses a steering wheel steering angle sensor device for an automobile electronic stability program. The steering wheel steering angle sensor device comprises a base (2), a first gear (1), a second gear (5), a third gear (4), a first magnet (6), a second magnet (3), a first magnetic inductive sensor (7) and a second magnetic inductive sensor (8), wherein the base is provided with three positioning grooves (21, 22 and 23); the first gear (1) is arranged in the first positioning groove (21); the second gear (5) is arranged in the second positioning groove (22); the third gear (4) is arranged in the third positioning groove (23); the first magnet (6) is fixed on the second gear (5); the second magnet (3) is fixed on the third gear (4); the first magnetic inductive sensor (7) and the second magnetic inductive sensor (8) are arranged on the base (2); the second gear (5) and the third gear (4) are in meshed connection with the first gear (1) respectively; the positions of the first magnet (6), the second gear (5) and the first magnetic inductive senor (7) are aligned; and the positions of the second magnet (3), the second magnetic inductive sensor (8) and the third gear (4) are aligned.

Method for monitoring a rotation of a compressor wheel

Abstract: The invention proposes a method for monitoring a rotation of a compressor wheel (12), in particular a compressor wheel (12) of an exhaust gas turbocharger, and an apparatus (10) for carrying out the method. The method according to the invention provides for the compressor wheel (12) to have a number n of blades (14) on the circumference, wherein a sensor (16) is provided for the purpose of detecting at least one rotation property of the compressor wheel (12), especially the speed or rotational speed, wherein the sensor (16) is an inductive sensor (16), wherein the sensor (16) generates at least one output signal (20) on the basis of the eddy currents generated by being guided past the blades (14), wherein the rotation property, in particular the rotational speed, of the compressor wheel (12) is inferred from a fundamental frequency of the output signal (20), and wherein an item of information relating to a fault of the compressor wheel (12) can also be gathered from at least one modulation of the output signal (20), in particular amplitude modulation. An imbalance of the compressor wheel can be detected, in particular.