Showing papers on "Inductive sensor published in 2014"

The Effect of Textile-Based Inductive Coil Sensor Positions for Heart Rate Monitoring

Abstract: In the research related to heart rate measurement, few studies have been done using magnetic-induced conductivity sensing methods to measure the heart rate. The aim of this study was to analyze the effect of the position of a textile-based inductive coil sensor on the measurement of the heart rate. In order to assess the capability of the textile-based inductive coil sensor and the repeatability of measured cardiac muscle contractions, we proposed a new quality index based on the morphology of measured signals using a textile-based inductive coil sensor. We initially explored eight potential positions of the inductive sensor in a pilot experiment, followed by three sensor positions in the main experiment. A simultaneously measured electrocardiography (ECG) signal (Lead II) which was used as a reference signal for a comparison of the R-peak location with signals obtained from selected positions of the textile-based inductive coil sensor. The result of the main experiment indicated that the total quality index obtained from the sensor position `P3', which was located 3 cm away from the left side from the center front line on the chest circumference line, was the highest (QI value = 1.30) among the three positions across all the subjects. This finding led us to conclude that (1) the position of the textile-based inductive coil sensor significantly affected the quality of the measurement results, and that (2) P3 would be the most appropriate position for the textile-based inductive coil sensor for heart rate measurements based on the magnetic-induced conductivity sensing principle.

Research on the Output Characteristics of Microfluidic Inductive Sensor

Abstract: This paper focuses on the output characteristic of the microfluidic inductive sensor. First the coil-metal particle system model is established from Maxwell’s equations. Then series solution is achieved by solving partial differential equation. Finally the numerical simulations and physical experiments are compared on particle feature, particle size, excitation frequency, coil turns, and coil density. The experiments coincide well with the simulations.

Inductive Sensor Performance in Partial Discharges and Noise Separation by Means of Spectral Power Ratios

Abstract: Partial discharge (PD) detection is a standardized technique to qualify electrical insulation in machines and power cables. Several techniques that analyze the waveform of the pulses have been proposed to discriminate noise from PD activity. Among them, spectral power ratio representation shows great flexibility in the separation of the sources of PD. Mapping spectral power ratios in two-dimensional plots leads to clusters of points which group pulses with similar characteristics. The position in the map depends on the nature of the partial discharge, the setup and the frequency response of the sensors. If these clusters are clearly separated, the subsequent task of identifying the source of the discharge is straightforward so the distance between clusters can be a figure of merit to suggest the best option for PD recognition. In this paper, two inductive sensors with different frequency responses to pulsed signals, a high frequency current transformer and an inductive loop sensor, are analyzed to test their performance in detecting and separating the sources of partial discharges.

A multi-coil Magneto-Inductive transceiver for low-cost wireless sensor networks

Abstract: A short-range low-cost Magneto-Inductive (MI) communication system is presented for wireless sensor network applications. The advantages of MI communications include the capability of communication in all conditions such as in air, underwater, and through solids. The hardware implementation and software design incorporate three coils for multi-channel receiving and transmission. Field tests have been conducted that demonstrate promising performance in terms of communication range and robustness against coil orientation mismatch.

A high sensitivity inductive sensor for blade tip clearance measurement

Abstract: A multiplexed inductive sensor consisting of multiple mini-sized planar spiral coils for detecting multiple tip clearances of rotor blades is presented. The sensor measures the tip clearances by monitoring the inductance changes of planar spiral coils caused by the passage of the rotor blades. A resonance frequency division multiplexing technique and parallel LC resonance measurement were applied to the multiple sensor coils, making it feasible to measure multiple tip clearances using only one set of measurement electronics with high sensitivity and resolution. The results from tests conducted on a bench-top test rig have demonstrated that the sensor is capable of simultaneously measuring multiple tip clearances from 0 to 5 mm with a 10 ?m resolution at a high rotary speed up to 80?000 RPM. With its high resolution, high sensitivity and capability of monitoring a large number of tip clearances simultaneously, this sensor can potentially be used for advanced active tip clearance control in turbine machinery.

Inductive Displacement Sensors with a Notch Filter for an Active Magnetic Bearing System

Abstract: Active magnetic bearing (AMB) systems support rotating shafts without any physical contact, using electromagnetic forces. Each radial AMB uses two pairs of electromagnets at opposite sides of the rotor. This allows the rotor to float in the air gap, and the machine to operate without frictional losses. In active magnetic suspension, displacement sensors are necessary to detect the radial and axial movement of the suspended object. In a high-speed rotating machine equipped with an AMB, the rotor bending modes may be limited to the operating range. The natural frequencies of the rotor can cause instability. Thus, notch filters are a useful circuit for stabilizing the system. In addition, commercial displacement sensors are sometimes not suitable for AMB design, and cannot filter the noise caused by the natural frequencies of rotor. Hence, implementing displacement sensors based on the AMB structure is necessary to eliminate noises caused by natural frequency disturbances. The displacement sensor must be highly sensitive in the desired working range, and also exhibit a low interference noise, high stability, and low cost. In this study, we used the differential inductive sensor head and lock-in amplifier for synchronous demodulation. In addition, an active low-pass filter and a notch filter were used to eliminate disturbances, which caused by natural frequencies. As a consequence, the inductive displacement sensor achieved satisfactory linearity, high sensitivity, and disturbance elimination. This sensor can be easily produced for AMB applications. A prototype of these displacement sensors was built and tested.

Electronic device and method for adjusting amount of electric power supplied to proximity sensor of the electronic device

Abstract: An electronic device includes a touch screen, a background light, and a proximity sensor. The electronic device sets a default value for an amount of electric power supplied to the proximity sensor and a rule for adjusting the amount of electric power supplied to the proximity sensor. When a calling function of the electronic device is started, the electronic device is enabled to supply the proximity sensor the amount of electric power having the default value, and determines if the proximity sensor detects an object near the touch screen with the amount of electric power having the default value. The electronic device increases or decreases the amount of electric power supplied to the proximity sensor according to the rule.

Methods for detecting mated coils

Abstract: Methods and systems for improved efficiency when an inductive power transmitter associated with an inductive power transfer system experiences a low-load or no-load condition. More particularly, methods and systems for detecting when an inductive power receiver is absent or poorly connected to an inductive power transmitter. The inductive power transmitter includes, in one example, a current peak monitor coupled to an inductive power transmit coil. The current peak monitor waits for a current peak resulting from spatial displacement of a magnetic field source within the inductive power receiver, indicating to the inductive power transmitter that the inductive power receiver is moving, or has moved, toward the inductive power transmitter. Other examples include one or more Hall effect sensors within the inductive power transmitter to monitor for the magnetic field source of the inductive power receiver.

Methods and apparatus for magnetic sensor having an externally accessible coil

Abstract: Methods and apparatus for magnetic field sensor having a sensing element, an analog circuit path coupled to the sensing element for generating an output voltage in response to a magnetic field applied to the sensing element, and a coil in proximity to the sensing element, the coil having a first terminal that is accessible external to the magnetic field sensor.

Adaptive touch sensing electrode

Abstract: Techniques for varying aggregate area of a sensor electrode used for capacitive sensing. Sensor electrodes are driven for capacitive sensing. Resulting signals are received from the sensor electrodes. Based on signal strengths of the resulting signals, aggregate area of the sensor electrodes may be varied. The aggregate area of the sensor electrodes may be varied by connecting or disconnecting segments of the sensor electrodes from a sensor module that drives the sensor electrodes for capacitive sensing. The ability to vary the aggregate area of the sensor electrodes expands the overall dynamic range of a receiver module coupled to the sensor electrodes.

Proximity sensor systems and methods of operating same

Abstract: Techniques for using photo detectors as tunable proximity sensors for detection of target objects and ascertaining their distance from the proximity sensors are disclosed. In one embodiment, the techniques may be realized as a proximity sensor system including a photo detector having a first doped region, a gate, a second doped region and a light absorbing region, a control circuitry for generating a plurality of control signals to be applied to the photo detector, and a signal detector to detect an output signal from the photo detector.

Methods, apparatuses and systems for sensing exposure of electronic devices to moisture

Abstract: Systems, devices and methods for sensing moisture within an electronic device are disclosed. A device may include a housing and a display defining an exterior of an electronic device and an interior of the electronic device. Further, the device may include an integrated circuit (IC) within the electronic device and a control element within the electronic device. The device may also include a moisture sensor such as an inductive sensor, a capacitance sensor, or both. The moisture sensor, which may be part of the IC, together with the control element may sense moisture within the electronic device.

Integrated brake control sensor

Abstract: A sensor assembly for a vehicle electronic braking system including a housing, at least one linear sensor, the at least one sensor contained within the housing, the linear sensor adapted to measure the linear distance traveled of a brake pedal. The assembly further includes a rotary sensor, the rotary sensor also contained within the same housing, the rotary sensor adapted to measure rotary motion of a DC motor in an the electronic braking system. The rotary sensor and the at least one linear sensor each in communication with a brake control unit. The at least one linear sensor and the at least one rotary sensor is encapsulated, either together or separately. The at least one linear sensor is a Hall-effect sensor. A wake up switch circuit is integrated with at least one of the linear sensors to wake up the system when the driver depresses the brake pedal in the electronic braking system. The rotary sensor is an inductive sensor.

Improvement in sensitivity of an inductive oil palm fruit sensor.

Abstract: Among palm oil millers, the ripeness of oil palm Fresh Fruit Bunch (FFB) is determined through visual inspection. To increase the productivity of the millers, many researchers have proposed with a new detection method to replace the conventional one. The sensitivity of such a sensor plays a crucial role in determining the effectiveness of the method. In our preliminary study a novel oil palm fruit sensor to detect the maturity of oil palm fruit bunches is proposed. The design of the proposed air coil sensor based on an inductive sensor is further investigated to improve its sensitivity. This paper investigates the results pertaining to the effects of the air coil structure of an oil palm fruit sensor, taking consideration of the used copper wire diameter ranging from 0.10 mm to 0.18 mm with 60 turns. The flat-type shape of air coil was used on twenty samples of fruitlets from two categories, namely ripe and unripe. Samples are tested with frequencies ranging from 20 Hz to 120 MHz. The sensitivity of the sensor between air to fruitlet samples increases as the coil diameter increases. As for the sensitivity differences between ripe and unripe samples, the 5 mm air coil length with the 0.12 mm coil diameter provides the highest percentage difference between samples and it is amongst the highest deviation value between samples. The result from this study is important to improve the sensitivity of the inductive oil palm fruit sensor mainly with regards to the design of the air coil structure. The efficiency of the sensor to determine the maturity of the oil palm FFB and the ripening process of the fruitlet could further be enhanced.

Inductive sensors based on embedded coil technology for nanometric inter-segment position sensing of the E-ELT

Abstract: The primary mirror of the E-ELT consists of a mosaic of 798 hexagonal mirror segments whose relative positions will be measured by 4524 so-called edge sensors. The main properties of these three axes edge sensors are nanometric precision, high linearity, low sensitivity to temperature and humidity fluctuations as well as high reliability. This paper presents the outcome of a development carried out by Micro-Epsilon in the framework of prototype activities launched by the European Southern Observatory several years ago. The performance of inductive sensors based on Embedded Coil Technology are presented as well as results obtained on representative operational conditions.

Touch display screen electronic price tag based on human body induction and operating method thereof

Abstract: The invention belongs to the technical field of price tags, and provides a touch display screen electronic price tag based on human body induction. The touch display screen electronic price tag based on human body induction comprises a shell, a host, a touch display screen, a voice device, a power source and a loudspeaker, wherein a human body inductive sensor, the host, the touch display screen, the voice device, the loudspeaker and the power source are arranged in the shell, the host is connected with the human body inductive sensor, and is used for receiving information indicating that a person gets close to the human body inductive sensor or is far away from the human body inductive sensor, and transmitting the inductive information, the touch display screen is connected with the host, is used for receiving the information indicating that the person gets close to the human body inductive sensor or is far away from the human body inductive sensor, is automatically lightened and displays related information of products when the person gets close to the human body inductive sensor, and can automatically sleep when the person is far away from the human body inductive sensor, the voice device and the power source are connected with the host, and the loudspeaker is connected with the voice device. The touch display screen electronic price tag based on human body induction has the advantages that the automatic lightening or sleep function and the automatic voice broadcast function are achieved when a human body gets close to the human body inductive sensor and is far away from the human body inductive sensor, product diversification introductions are achieved through the touch display screen, manpower is saved, the cost is reduced, and product information can be conveniently updated or changed.

Alternative input device for press/release simulations

Abstract: A device and method in accordance with the present disclosure provide alternate inputs to an electronic device having at least one of an optical sensor or a proximity sensor. An object is placed relative to at least one of the at least one proximity sensor or optical sensor, and the object is detected as an input to the electronic device based on an amount of light detected by the optical sensor or a proximity of the object relative to the electronic device as determined by the proximity sensor. The detected input is equated to a predetermined function of the electronic device.

Optimized magnetic sensors to measure speed and position in adverse environments

Abstract: The paper reviews features and applications of the modified inductive sensor, able to operate in contact with exhaust gases of temperature even as high as 1200 K. The new design includes the metal-ceramic housing ensuring proper heat transfer, the magnetic circuit containing set of permanent magnets with various magnetic field values and Curie temperatures, the completely redesigned windings and current/voltage converter used instead of the electromotive force amplifier. Its principle of operation is based on electrodynamical interaction and therefore it may be referred as a passive eddy-current sensor. Two applications of the technique are presented such as blade vibration measurement in High Pressure Turbine of military turbofan (tip-timing) and speed monitoring of roller-element bearing supporting the shaft in a turbojet engine.

Faucet including capacitive and ultrasonic sensing

Abstract: A fluid delivery apparatus includes a spout, an ultrasonic sensor, and a capacitive sensor. The ultrasonic sensor is configured to detect the presence of a user adjacent the spout when enabled. The capacitive sensor is configured to define a capacitance sensing field in an area near the spout and also to detect a presence of a user. A controller is coupled to the capacitive sensor and the ultrasonic sensor. The controller is programmed to detect the presence of a user in the capacitance sensing field based on an output signal from the capacitance sensor. The controller is also programmed to enable the ultrasonic sensor in response to detecting the presence of the user in the capacitance sensing field with the capacitive sensor, thereby reducing the amount of power used by the ultrasonic sensor.

Driving sensor electrodes for proximity sensing

Abstract: In an example, a processing system includes: a sensor module comprising sensor circuitry, the sensor module configured to: drive, during a first time period, a first sensor electrode of a first plurality of sensor electrodes for absolute capacitive sensing, a second sensor electrode of the first plurality of sensor electrodes with a reference signal, and at least one sensor electrode of a second plurality of sensor electrodes with a guard signal, to acquire first changes of capacitance between the first sensor electrode and at least one input object in proximity with the first sensor electrode; and a determination module configured to determine positional information for the at least one input object based at least in part on changes of capacitance acquired by the sensor module.

A New Inductive Proximity Sensor Based Guiding Tool to Locate Metal Shrapnel During Surgery

Abstract: Shrapnel injury is a major cause of death in victims of bomb blast, land mines, and gun fire. Currently, doctors rely on imaging systems to locate the shrapnel before surgery. But, since these images do not provide any real-time information of the location of the shrapnel, effectiveness of surgery solely depends on the doctors' skill to trace them. Therefore, in some cases, the shrapnel, in spite of being visible in the images, may become untraceable during surgery. Hence, an online tool that can help the surgeon in finding the location of the shrapnel during the surgery will be very effective. A prototype of such a tool has been realized using an inductive proximity sensor (IPS). The new IPS is small enough for inserting into the victim's body. Since the detection depth (DD) of an IPS decreases with its diameter, this IPS uses a differential sensing scheme for detection. Hence, the new sensor achieves DDs longer than its diameter. The design of the sensor takes care of the effects of parasitic parameters that become predominant as the size gets smaller and ensures repeatable results. The tool also features a special excitation scheme that has multiple advantages when compared with existing schemes. The details of the sensor, its excitation and performance against different targets under various conditions are presented in this paper.

A co-planar, near field communication telemetry link for an analyte sensor

Abstract: An inductive sensor system for remote powering and communication with an analyte sensor (e.g., a fully implantable analyte sensor). The system may include an analyte sensor and transceiver. The system may be ferrite-enhanced. The transceiver may implement a passive telemetry for communicating with the analyte sensor via an inductive magnetic link for both power and data transfer. The link may be a co-planar, near field communication telemetry link. The transceiver may include a reflection plate configured to focus flux lines linking the transceiver and the sensor uniformly beneath the transceiver. The transceiver may include an amplifier configured to amplify battery power and provide radio frequency (RF) power to a transceiver antenna.

Modeling and Compensation of Thermal Effects on an Ironless Inductive Position Sensor

Abstract: The ironless inductive position sensor can be the ideal candidate for linear position sensing in harsh environment and in the presence of external magnetic fields. Starting from the validated electromagnetic characteristics, this paper presents a model of thermal effects influencing the sensor's position reading and an effective algorithm to compensate them. The compensation is performed without affecting the nominal sensor's functioning and without using additional temperature probes, which would complicate the sensor's assembly. The model constitutes the basis of this algorithm, which is then validated through experimental measurements on a custom ironless position sensor prototype.

Investigation system for road traffic flow and realization method thereof

Abstract: The invention discloses an investigation system for road traffic flow and a realization method thereof, wherein the road traffic flow investigation system includes a magnetic-core inductive sensor, a signal processing circuit, a data acquisition circuit and a data processing system, which are mutually connected in order. The magnetic-core inductive sensor includes a first coil, a second coil and a magnetic coil. The signal processing circuit carries out filtering and amplifying on signals. The data acquisition circuit converts analog signals into digital signals. The data processing system carries out calculation and statistics on input digital signals and obtains traffic flow information which includes vehicle model, vehicle speed and traffic flow. The adopted magnetic-core inductive sensor not only has the characteristics of being small in size, simple to install and small in road damaged surfaces, but is also high in signal intensity and obvious in vehicle-model features corresponding to output waveform. Moreover, the investigation system for the road traffic flow adopts an RBF neural network to carry out vehicle-model identification so that vehicle-model identification rate is high.

Device useful for e.g. clamping, stamping, welding of components used in the car body of motor vehicle industry, comprises elongated adjusting part, sensor device with electrical or inductive sensors or micro-switches and control device

Abstract: Device comprises: an elongated adjusting part driven straight by a drive in opposite directions, which has a device part pivotable in a housing (1) arranged in a toggle lever e.g. a clamping hook, a welding electrode, an engraved stamp or swing arm drives; a sensor device with electrical or inductive sensors or micro-switches which detect the position of elongated adjusting part and transmit the values via signal lines to a display device; and control device. The sensor device is configured cartridge-shaped or prismatic sensor, which is insertable or screwed in a lateral recess of housing. Device comprises: an elongated adjusting part driven straight by a drive in opposite directions, which has a device part pivotable in a housing (1) arranged in a toggle lever e.g. a clamping hook, a welding electrode, an engraved stamp or swing arm drives; a sensor device with electrical or inductive sensors or micro-switches which detect the position of the elongated adjusting part and transmit the values via signal lines to a display device; and control device. The sensor device is configured cartridge-shaped or prismatic sensor, which is insertable or screwed in a lateral recess of the housing and has damped sensors on its end pointing into the interior of the housing portion. A rod is arranged against the restoring force of a spring element in the interior of the housing with its longitudinal axis parallel to the longitudinal axis of the elongate adjusting part, where the rod has a switching element at its end portion which is in the form of a compression spring opposite to spring element, and attenuates one of the two sensors.

Wheel sensor, particularly for train detection system, has inductive sensor for detecting magnetic field change as result of iron wheels of rail vehicle, where inductive sensor is arranged at side of rail of track

Abstract: The wheel sensor has an inductive sensor (1) for detecting a magnetic field change as a result of the iron wheels of a rail vehicle. The inductive sensor is arranged at a side of a rail (2) of the track. The inductive sensor comprises a transmitting coil (4) and two receiving coils (5,6). The receiving coils have adjacent partial coils (5.1,5.2,6.1,6.2) connected in series in anti-phase. The partial coils are parametrized identically.

Combining sensor electrodes in a matrix sensor

Abstract: A display device having a capacitive sensing device, a processing system, and a method are provided for detecting presence of an input object using a capacitive sensing device having a plurality of sensor electrodes arranged in a matrix. The described technique programmatically combines multiple sensor electrodes into a larger sensor electrode for absolute capacitive sensing. The sets of sensor electrodes that are combined may be selectively coupled based a window size and a step size associated with a number of sensor electrodes in common between the sets.