Inductive sensor

About: Inductive sensor is a research topic. Over the lifetime, 2282 publications have been published within this topic receiving 21984 citations.

Pulsed excited proximity sensor

Abstract: A proximity sensor (10) has a transducer coil (18) that is part of an oscillator circuit. The oscillating signal varies as a function of the presence or absence of a metallic object adjacent the transducer coil (18). By analyzing selected characteristics of that oscillating signal, the presence of and object and the distance to the object can be determined. Other analysis techniques enable the sensor to distinguish between ferrous and non-ferrous materials. A mechanism (130-140) also is provided to automatically configure operation of the proximity to avoid interference from another adjacent proximity sensor (10).

A combined inductive-capacitive proximity sensor and its application to seat occupancy sensing

Abstract: This paper presents a simple yet efficient proximity sensor obtained by combining inductive and capacitive sensing principles. Capacitive proximity sensors based on shielding of electric field are known for detecting presence of humans in its vicinity. Such systems may fail to distinguish the proximity of a human from grounded conductive objects. A novel, cost effective, sensing scheme that uses a single sensor, which performs both the inductive and capacitive proximity mode of operation is proposed in this paper. The measurement system uses a signal conditioning unit based on a carrier frequency principle. A prototype sensing system has been built and its application as a seat occupancy sensing system in a vehicle has been verified. The developed system successfully senses human proximity and distinguishes it from other conductive objects.

Highly sensitive flexible proximity tactile array sensor by using carbon micro coils

Abstract: Recently, the new generation of robotics, called soft robotics, are exploited by soft materials as the revolutionary tools which innovate the current challenges. In this paper, we propose a novel dual mode array sensor based on the carbon microcoils (CMC) in soft dielectric elastomer substrate material. It can detect the distance to the object as well as the pressure when it has contact. In the first, the design of sensor structure and its properties are investigated. Various experiments are performed on the dielectric substrates, electrode structures, and the target objects by changing electrical impedance formed by CMC under the alternating current (AC) excitation voltage with the dominant excitation frequency at 100 kHz. Secondly, the tactile sensing, and proximity sensing, that is dual mode sensing performance are examined with respect to repeatability, reversibility, durability, sensitivity, and hysteresis. In the next, the sensor signal processing for measuring impedance (LCR) are analyzed with an analog signal processing, analog switching circuit, and digital processing. Finally, we successfully demonstrate the performance of 10 × 10 proximity tactile sensor which is capable of detecting a 30 mg (300 mgF) droplet and applied pressure up to 330 kPa approximately, and detected the distance of the metal object from 150 mm to touch on to the CMC sensor surface. Moreover, the 16 × 16 multi-cell arrays tactile sensor with 2 mm electrode pads spatial-resolution activated in 32 mm × 32 mm × 0.6 mm is performed to show the high resolution performance as well as multiple touches on independent cells.

Inductive sensor for monitoring fluid level and displacememt

Abstract: A sensor system for measuring the level of a fluid includes a tube having a primary coil and a pair of secondary coils wound thereabout. The secondary coils have a periodically varying winding density distribution. The winding density distribution of one secondary coil is shifted relative to the winding density distribution of the other secondary coil. A float positioned adjacent the tube modifies an electromagnetic field produced by the primary coil. In response to the modified electromagnetic field, the first and second secondary coils produce first and second signals having amplitudes that vary periodically in response to the movement of the float between the ends of the tube.

Method for the non-invasive sensing of physical matter on the detection surface of a capacitive sensor

Abstract: A capacitance sensor detects the absence/presence of physical matter on a sensing surface of the sensor. The capacitive sensor is a multi-cell sensor wherein each cell has one or more buried, protected, and physically inaccessible capacitor plates. The sensor is physically placed in an environment that is to be monitored for deposition of a particle, vapor, and/or drop of a foreign material on the sensing surface. All cells are initially placed in a startup condition or state. Thereafter, the cells are interrogated or readout, looking for a change in the equivalent feedback capacitance that results from an electrical field shape modification that is caused by the presence of physical matter on the sensing surface. When no such change is detected, the method is repeated for another cell. When a change is detected for a cell, a particle/vapor/drop output is provided. As an optional step, the sensor is provided with a layer of a material that is selectively reactive to or reactive with, a particle/vapor/drop of a known type of foreign material.