Showing papers on "Inductive sensor published in 2018"

Design and Development of a New Non-Contact Inductive Displacement Sensor

Abstract: A new, non-contact, planar spiral coil-based inductive displacement sensor is presented in this paper. The proposed sensor employs a fixed planar coil and a movable $U$ -shaped magnetic core. The sensor is designed such a way that the shape of inductance versus displacement $x$ is sinusoidal. Due to this feature, the value of $x$ is obtained easily from the inductance measured without the need of a look-up table, which is not the case for most of the planar coil-based sensors. The proposed sensor has very low sensitivity to vertical misalignment of the core. A phase-sensitive detector-based measurement scheme is employed to measure the inductance. The inductance characteristic of the proposed sensor is symmetric with respect to the center of the coil. A simple capacitive detection scheme to distinguish the position of the core between the two halves of the coil is proposed in this paper. This method enables to extend the sensor range with multiple coils connected in series. A prototype of the proposed sensor has been developed and tested. The sensor has a worst case error of 0.6%. A modified sensor using two coil sets has been developed. The modified sensor has high sensitivity over its entire range, unlike the first prototype. It has a worst case error of 0.2% and a resolution of 6.5 $\mu \text{m}$ . The low-cost sensor developed will be useful for many industrial linear position sensing applications.

A Flexible, Planar-Coil-Based Sensor for Through-Shaft Angle Sensing

Abstract: In this paper, a simple angle sensor is presented, which is easy to fabricate and is low cost. The sensor is constructed using square shaped flexible planar coils, bent, and arranged in a cylindrical pattern. The sensor design was verified using appropriate analytical design, and an algorithm to identify the quadrants of the measured angle was developed. The output of the sensor is tolerant toward errors due to the axial displacement of the sensing coil. This makes it suitable for applications where the shaft may be subjected to axial motion (even up to 30% of sensing coil length) in addition to angular motion. The radial space required for the existing through-shaft angle sensors is large. Although capacitive sensors can be employed, their output is sensitive to moisture, dust, and oil. The proposed sensor requires very small radial space (about 1.5mm) and its output is not sensitive to such environmental parameters. A prototype sensor was constructed to verify the sensor operation and to evaluate its performance. The prototype sensor had an rms error of 0.58% and the maximum error was within ±1%. The resolution of the measurement system was estimated to be 0.15°. A detailed error analysis has been conducted and the outcome shows that the output of the sensor has very low sensitivity to the source of errors.

A high sensitive multi-parameter micro sensor for the detection of multi-contamination in hydraulic oil

Abstract: A high sensitive multi-parameter micro sensor consisted of a microfluidic chip and a sensing unit is presented The sensing unit, which composed of a dual-coil and two silicon steel sheets, is embedded in the simple microfluidic chip with a straight microchannel structure The micro sensor can be used not only as an inductive sensor to distinguish between ferromagnetic and non-ferromagnetic metal particles, but also as a capacitive sensor to distinguish between water droplets and bubbles in hydraulic oil The simulation results show that both the magnetic field and the electric field of the sensing unit are enhanced under the effect of the silicon steel sheets In the experiments, the number of turns of the coil was optimized first, and then the comparative experimental results show that the detection amplitudes of both iron and copper particles were increased about four times compare with the sensing unit without silicon steel sheets, which verified the simulation results Using the simple micro sensor, without any complicated external circuits, in the inductance detection experiments, we demonstrate the successful detection of 33 μm iron particles and 90 μm copper particles in hydraulic oil; and in the capacitance detection experiments, we can detect 100 μm water droplets and 180 μm bubbles in hydraulic oil For both the inductance and capacitance detection, the results of particles with different sizes were in good agreement with the simulation results

A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique

Abstract: Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

Monitoring of Non-Ferrous Wear Debris in Hydraulic Oil by Detecting the Equivalent Resistance of Inductive Sensors

Abstract: Wear debris in hydraulic oil contains important information on the operation of equipment, which is important for condition monitoring and fault diagnosis in mechanical equipment. A micro inductive sensor based on the inductive coulter principle is presented in this work. It consists of a straight micro-channel and a 3-D solenoid coil wound on the micro-channel. Instead of detecting the inductance change of the inductive sensor, the equivalent resistance change of the inductive sensor is detected for non-ferrous particle (copper particle) monitoring. The simulation results show that the resistance change rate caused by the presence of copper particles is greater than the inductance change rate. Copper particles with sizes ranging from 48 μm to 150 μm were used in the experiment, and the experimental results are in good agreement with the simulation results. By detecting the inductive change of the micro inductive sensor, the detection limit of the copper particles only reaches 70 μm. However, the detection limit can be improved to 48 μm by detecting the equivalent resistance of the inductive sensor. The equivalent resistance method was demonstrated to have a higher detection accuracy than conventional inductive detection methods for non-ferrous particle detection in hydraulic oil.

Metamaterial absorber for THz polarimetric sensing

Abstract: THz encoders have distinct advantages for position sensing compared with other types of encoders, such as those based on optical and inductive sensors. A polarization-dependent metamaterial absorber reflects one polarization while absorbs the other, which makes it an ideal building block for the barcode of a THz encoder system. In this paper, we present the design, fabrication, and experiments of a THz polarization-dependent metamaterial absorber, and its application to a polarimetric sensing system.

Differentiation of nonferrous metal particles in lubrication oil using an electrical conductivity measurement-based inductive sensor.

Abstract: A method that measures the electrical conductivity of metal based on monitoring the inductance changes of coils via an inductive sensor is introduced in this work to differentiate metal particles in lubrication oil Theoretical analysis coupled with experimentation is employed to differentiate varieties of nonferrous metal particles, including copper and aluminum particles, ranging from 860 μm to 880 μm in diameter The results show that the inductive sensor is capable of the identification and differentiation of nonferrous metal particles in lubrication oil based on the electrical conductivity measurement The concept demonstrated in this paper can be extended to inductive sensors in metal particle detection and other scientific and industrial applications

Experimental Investigation of High Temperature-Resistant Inductive Sensor for Blade Tip Clearance Measurement

Abstract: Turbine tip clearance of aero-engine is important to engine performance. Proper control of rotor tip clearance contributes to engine efficiency improvement and fuel consumption reduction. Therefore, accurate tip clearance measurement is essential. The inductive measurement method is one of the non-contact distance measurement methods, which has the characteristics of high sensitivity, fast response speed and strong anti-interference ability. Based on the principle of inductive sensor measuring tip clearance, the ambient temperature change will cause the material electromagnetic performance change for the conductivity and permeability varies with temperature. The calibration experiment was conducted to obtain the sensor resolution and sensing range. The effect of temperature on sensor parameters was extracted from high temperature experiment data. Results show the resolution of planar coil made of platinum wire can be 10 μm and the maximum sensing range can reach 5 mm. At temperature from 500 ℃ to 1100 ℃, coil inductance almost does not change with temperature while coil resistance varies exponentially with temperature, that means the coil inductance variation can reflect the tip clearance change and resistance can indicate the measuring temperature.

A novel approach of using a planar inductive position sensor for the Permanent magnet synchronous motor control application

Abstract: Permanent magnet synchronous motors (PMSM) are taking over the commercial, industrial (robotics) and automotive industry. Most of the applications demand high starting torque at zero speed. For generating the desired amount of torque at zero speed, accurate rotor position information is necessary, which is obtained by using position sensors. Hall sensors with digital output are sensitive to temperature and external magnetic fields and do not offer high resolution. Optical encoders provide good resolution but lead to higher cost and reliability related issues in the harsh/contaminated environment. Inductive sensing technology is an emerging technology which can be used in wide range of application such as proximity, angular displacement, linear displacement etc. PMSM control is one such application that can make use of planar Inductive position sensors which are contactless sensors, works on LVDT principle. These can be inexpensively built with stationary printed circuit board PCB coils and metal target. Inductive sensors are absolute devices which mean that they need no motion at power up to determine position. This paper covers planar inductive position sensor and its usage in PMSM control application. The experiments are carried out to substantiate the proposed technique in the speed controlled drive system of PMSM.

Triple Flat-Type Inductive-Based Oil Palm Fruit Maturity Sensor.

Abstract: This paper aims to study a triple flat-type air coil inductive sensor that can identify two maturity stages of oil palm fruits, ripe and unripe, based on the resonance frequency and fruitlet capacitance changes. There are two types of triple structure that have been tested, namely Triple I and II. Triple I is a triple series coil with a fixed number of turns (n = 200) with different length, and Triple II is a coil with fixed length (l = 5 mm) and a different number of turns. The peak comparison between Triple I and II is using the coefficient of variation cv, which is defined as the ratio of the standard deviation to the mean to express the precision and repeatability of data. As the fruit ripens, the resonance frequency peaks from an inductance⁻frequency curve and shifts closer to the peak curve of the air, and the fruitlet capacitance decreases. The coefficient of the variation of the inductive oil palm fruit sensor shows that Triple I is smaller and more consistent in comparison with Triple II, for both resonance frequency and fruitlet capacitance. The development of this sensor proves the capability of an inductive element such as a coil, to be used as a sensor so as to determine the ripeness of the oil palm fresh fruit bunch sample.

Analysis of Electrical Resonance Distortion for Inductive Sensing Applications

Abstract: Resonating inductive sensors are increasingly popular for numerous measurement techniques, not least in non-destructive testing, due to the increased sensitivity obtained at frequencies approaching electrical resonance. The highly unstable nature of resonance limits the practical application of such methods while no comprehensive understanding exists of the resonance distorting behavior in relation to typical measurements and environmental factors. In this paper, a study into the frequency spectrum behavior of electrical resonance is carried out exploring the effect of key factors. These factors, known to distort the electrical resonance of inductive sensors, include proximity to (or lift-off from) a material surface and the presence of discontinuities in the material surface. Critical features of resonance are used as metrics to evaluate the behavior of resonance with lift-off and defects. Experimental results are compared with results from a 2-D finite element analysis model that geometrically mimics the inductive sensor used in the experiments, and with results predicted by an equivalent circuit transformer model. The findings conclusively define the physical phenomenon behind measurement techniques such as near electrical resonance signal enhancement and show that lift-off and defect resonance distortions are unique and measurable and can be equated to exclusive variations in the induced variables in the equivalence circuit model. The resulting understanding found from this investigation is critical to the future development and understanding of a complete model of electrical resonance behavior, integral for the design of novel sensors, techniques, and inversion models.

Detection of foreign particles in lubrication oil with a microfluidic chip

Abstract: Purpose The purpose of this paper is to help understand the mathematical model of inductive sensor and to improve the sensitivity of nonferrous metal particle detection. Design/methodology/approach The expression of impedance change is established, while the distribution regularities of the magnetic field inside and outside the metal particle are obtained based on the Maxwell equations in complex forms, the analytic solution of the electromagnetic field is obtained and the experiment validation is implemented. Findings The expression of impedance and the analytic solution of the electromagnetic field are obtained. It is shown that the inductance change is more obvious than resistance change for the iron particles, but for copper particles, resistance change is more obvious and the resistance change increases with the frequency. In this work, copper particles (size: 20 µm) are detected at 2 MHz excitation frequency, and the imaginary part of impedance changes without adding any device, which is provided with a prominent guideline for detection of nonferrous particles of size less than 100 µm. Originality/value The expression of impedance change is established, the analytic solution of the electromagnetic field is obtained and copper particles (size: 20 µm) are detected at 2 MHz excitation frequency, and the imaginary part of impedance change without adding any device, which is provided with a prominent guideline for detection of nonferrous particles of size less than 100 µm.

Realization of Fractional Order Inductive Transducer

Abstract: In this paper, a new fractional order reluctance inductive transducer is realized by combining a basic reluctance inductive transducer with a general impedance converter circuit and a fractional order element. The fractional order element is realized using an RC ladder network attained by the integer-order rational approximation of the fractional term. A prototype of the fractional order reluctance inductive sensor was developed using the ferrite E-core-shaped variable reluctance inductive sensor and used for analyzing its characteristics. The impedance of the prototype device attained theoretically is validated with the experimental results. Hay’s bridge-based conditioning circuit is used with the fractional order inductive transducer to get the voltage output for the given input displacement; the output measured depends on the order of the fractional element. A suitable fractional order for which the output is both higher and linear is identified and presented. Through simulation and the experimental results obtained from the prototype transducer, it is demonstrated that the fractional-order inductive transducer is more effective in reducing the nonlinearity inherent in the real system with a considerable improvement in the sensitivity.

An Efficient Digital Converter for a Non-Contact Inductive Displacement Sensor

Abstract: A sigma-delta type displacement-to-digital converter suitable for a non-contact inductive displacement sensor is presented here. The constituents of a conventional sigma-delta scheme have been suitably modified so that a non-contact inductive displacement sensor excited by a sinusoidal voltage source becomes integral to the delta modulator. The conversion logic is designed such that the digital output of the proposed converter directly indicates the displacement that is being sensed. The results obtained from simulation studies and an emulated sensor model establishes the functionality of the proposed converter. Experimentation conducted on a PCB-based prototype sensor unit built in the laboratory further corroborates the efficacy of the proffered scheme.

The Effectiveness of Segregation Recyclable Materials by Automated Motorized Bin

Abstract: Recycling bins that have been introduced in the 3R campaign (Reduce, Reuse, and Recycle) are not optimally used by Malaysians. The research is an initiative to sort recyclable materials. The proposed research is an invention of automated isolation recycling bin where the bin equipped with several electronics components such as sensors and motors. The purpose of the sensors and motors are to enable the isolation process so it can be completed automatically with the aid Arduino Uno program. The installation of three types of sensors which are inductive sensor, capacitive sensor and infrared sensor will detect the type of recyclable materials that are inserted into the bin. Circular plate and pusher will be driven by DC motor to three compartments which are the bins for metal, paper and plastic. However, the materials will be discarded when the pusher plate is triggered by DC motor. The process of analyzing the effectiveness of this invention can be accomplished by recording the time taken for the product to separate the recyclable materials.

TBM hob full-state real-time on-line monitoring system and measurement method thereof

Abstract: The invention discloses a TBM hob full-state real-time on-line monitoring system and a measurement method thereof. The system comprises an inductive sensor, a Hall component, a strain gauge and a sensor base. The inductive sensor and the Hall component are arranged in the sensor base. The inductive sensor corresponds to a cutter ring of a TBM hob. The TBM hob is provided with a magnetic block which is opposite to the Hall component. A shaft hole of the TBM hob is provided with a support wedge block and a tensioning wedge block. The strain gauge is arranged in the support wedge block. A signalprocessing unit is arranged in the sensor base. The inductive sensor, the Hall component and the strain gauge are connected to the signal processing unit. The signal processing unit is connected to aTBM upper computer through a wireless communication module. In the invention, four index parameters of an abrasion loss of the TBM hob, a rotation speed of the TBM hob, a stress of the TBM hob and a working temperature of the TBM hob can be monitored; and through real-time monitoring, a working state of the TBM hob can be timely controlled and a damaged condition of the TBM hob can be timely knownso that the TBM hob can be timely repaired or replaced.

Designing a Rogowski Coil with Particle Swarm Optimization

Abstract: Rogowski coils are inductive sensors based on Faraday’s and Ampere’s Laws to measure currents through conductors without galvanic contact. The main advantage of Rogowski coils when compared with current transformers is the fact that the core is air so they never saturate and the upper cut-off current can be higher. These characteristics make Rogowski coils ideal candidates to measure high-amplitude pulsed currents. However, there are two main drawbacks. On the one hand, the output voltage is the derivative of the primary current so it has to be integrated to measure the original signal; on the other hand, the transfer function is resonant as a result of the capacitance and the self-inductance of the coil. The solution is the use of a passive integration with a terminating resistor at the output of the sensor that splits the two complex poles and gives a constant transfer function for a determined bandwidth. The downside is a loss of sensitivity. Since it is possible to calculate the electrical parameters of the coil based on its geometrical dimensions, the geometry can be adapted to design sensors for different applications depending on the time characteristics of the input current. This paper proposes the design of Rogowski coils based on their geometric characteristics maximizing the gain-bandwidth product using particle swarm optimization and adapting the coils to the specific requirements of the application.

Characterization of High- $Q$ Inductors Up to its Self-Resonance Frequency for Wireless Power Transfer Applications

Abstract: The primary coil of an efficient asymmetric inductive link (IL) has a high quality factor and operates near its self-resonance frequency (SRF). Therefore, its characterization is challenging, especially because the measurement instruments must be able to measure a large reactance and a very small resistance at a frequency where the inductor radiates. In this letter, we present a method suitable for characterizing high- $Q$ inductors up to its SRF. The proposed method uses an inductive sensor to characterize the inductor under test without galvanic contact. The method was validated by applying it to the primary coil of an asymmetric IL. The empirical results are consistent with the theoretical model and the full-wave simulations.

A Novel Approach to Measuring Separation Process of Oil–Saline Using Differential Electromagnetic Inductive Sensor and FPGA-Based Impedance Analyzer

Abstract: Liquid–liquid separation is an important process in many chemical engineering applications. The ability to monitor this process, in particular with a non-contact method, is of high value. This paper proposes and implements a novel sensing system adopting a differential electromagnetic inductive sensor and a field-programmable gate array-based impedance analyzer to monitor the separation processes of an oil-in-saline liquid system. The inductive sensor has a concentric cylinder structure with its coils arranged differentially. It is optimized to achieve a homogeneous sensitivity distribution in the sensing region. Electrical models of the oil-saline separation processes are established. Experiments under different oil and saline fractions, different agitation speeds, and durations are conducted to validate the capability of the system.

Indutivo: Contact-Based, Object-Driven Interactions with Inductive Sensing

Abstract: We present Indutivo, a contact-based inductive sensing technique for contextual interactions. Our technique recognizes conductive objects (metallic primarily) that are commonly found in households and daily environments, as well as their individual movements when placed against the sensor. These movements include sliding, hinging, and rotation. We describe our sensing principle and how we designed the size, shape, and layout of our sensor coils to optimize sensitivity, sensing range, recognition and tracking accuracy. Through several studies, we also demonstrated the performance of our proposed sensing technique in environments with varying levels of noise and interference conditions. We conclude by presenting demo applications on a smartwatch, as well as insights and lessons we learned from our experience.

Design of an inductive pickup type displacement transducer using an electro-optic effect of lithium-niobate-based Mach–Zehnder interferometers

Abstract: In this study, an improved inductive pickup coil and an electro-optic type displacement transmitter has been proposed. A modified differential inductance bridge network has been used to generate electrical signals and Mach–Zehnder interferometer (MZI) converts an electrical signal into an optical signal. The sensitivity of the sensor part of the transducer is very good because of two parallel magnetic paths for the inductive pickup. The theoretical equations explaining the operation of the transducer are derived. The proposed transducer is tested experimentally to obtain the static characteristics. The characteristics of the MZI-based displacement transmitter have been observed by using PC-based Opt wave Opti-BPM.v.9 simulation software in the linear zone. The experimental and simulated results are reported in this study. Very good linear characteristics of the transducer with adjustable sensitivity have been observed. The transmitter output in the form of normalised intensity of light is also found to be linearly related with displacement. The theoretical equations derived in this are found to support the experimental characteristics to a very good extent.

An Inductive Sensor for Water Level Monitoring in Tubes for Water Grids

Abstract: The sensors for monitoring different parameters in smart cities are becoming a hot topic for researchers all around the world. The smart grids are one of the main objectives of the smart city concept. In this paper, we present an inductive sensor for monitoring the water level in tubes for water distribution grids. Different prototypes are proposed and tested. All of the prototypes are composed of two copper coils, which are fed with a sine wave with an amplitude of 3.3V peak-to-peak. The proposed sensor is based on the measurement of the changes in the induced magnetic field when the medium changes. The sensor is placed inside the tube and it is able to detect the amount of water contained in the tube. The prototypes are tested with the tube full of water and the tube empty of water at different frequencies in order to found the best working frequency. Then, more data is gathered with the selected frequencies and different percentages of water amount in the tube. After testing the different prototypes we conclude that the best one is the prototype 4, which presents a voltage variation higher than 1 V. It is formed by two solenoidal coils of 0.4 mm of copper in form of half-circle with 55 spires. This sensor can be used for detecting obstruction in the water distribution network, sewerage, and leaks of water. This sensor can be connected to a node as Arduino Uno in order to transmit the gathered data to the database of the water supplier.

Using finite element modelling and experimental methods to investigate planar coil sensor topologies for inductive measurement of displacement

Abstract: The usage of planar sensors is widespread due to their non-contact nature and small size profiles, however only a few basic design types are generally considered. In order to develop planar coil designs we have performed extensive finite element modelling (FEM) and experimentation to understand the performance of different planar sensor topologies when used in inductive sensing. We have applied this approach to develop a novel displacement sensor. Models of different topologies with varying pitch values have been analysed using the ANSYS Maxwell FEM package, furthermore the models incorporated a movable soft magnetic amorphous ribbon element. The different models used in the FEM were then constructed and experimentally tested with topologies that included mesh, meander, square coil, and circular coil configurations. The sensors were used to detect the displacement of the amorphous ribbon. A LabView program controlled both the displacement stage and the impedance analyser, the latter capturing the varying inductance values with ribbon displacement. There was good correlation between the FEM models and the experimental data confirming that the methodology described here offers an effective way for developing planar coil based sensors with improved performance.

Structure design and simulation analysis of inductive displacement sensor

Abstract: Inductive displacement sensor is one kind of the common sensors widely used in magnetic bearing system. In this paper, the output characteristics of the differential inductive sensor are analyzed. One radial inductive displacement sensor was designed for a magnetic levitated rotor. The magnetic field distribution and output characteristics of the designed sensor were simulated by using FEA software. Theoretical analysis and simulation results both show that there is a very good linear relationship between the output voltage and the rotor displacement of differential inductive displacement sensor. And when the displacement of rotor is in the range of −0.2 to 0.2(mm), the sensor sensitivity presented by simulation is 16.9V/mm, equal to 67.6% of the given theoretical value. The main reason is that it is assumed that the sensor iron core coils are ideal and have no magnetic flux leakage in the theoretical analysis, which does not fit with well the practical conditions. The main reason is caused by the ignoring leakage inductance of the coil in theoretical analysis.

An Eddy Current-Capacitive Crack Detection Probe with High Insensitivity to Lift-Off

Abstract: This paper proposes a novel probe for reliable detection of crack/defect in a conductive target. This probe is realized by combining the eddy current and capacitive sensing techniques. Lift-off is a main concern for the eddy current based defect detection systems as the output of the sensor is very sensitive to the air gap between the target and the probe. The effect is significant when the probe is kept close to the target. In the proposed probe, like in some of the conventional ones, a planar coil is used as the eddy current sensing element. The same planar coil is used as a capacitive sensing element to sense the value of the capacitance between the coil and the target. This value is a function of the air gap between the probe and the target. The measured value is fed back to a magnetic actuator on which the entire probe is fitted. The magnetic actuator uses the capacitance value information and automatically adjusts the gap between the probe and the target to a preset value. Thus, the liftoff is corrected automatically. The functionality of the new probe has been analyzed and optimized using finite element analysis before building a prototype probe. Tests conducted on the probe developed confirms the effectiveness of the probe.

Device for two-way detection of the approach of a portable apparatus for hands-free access to a vehicle and associated detection method

Abstract: The present invention relates to a device for two-way detection (D') of the approach of a portable apparatus (P) for near-field hands-free access to a vehicle, said device (D') including a communication antenna (A) having a near-field communication frequency (Fc), the device including: a first passive inductive sensor (S1) oriented towards the outside of the vehicle (EXT), a second passive inductive sensor (S2) oriented towards the inside of the vehicle (INT), the two sensors being arranged so as to face one another, separated by a ferrite (F), and receiving the electromagnetic field emitted by the communication antenna, and being capable of detecting the approach of the portable apparatus; means (M1) for measuring a first voltage (V1) across the terminals of the first sensor and means (M2) for measuring a second voltage (V2) across the terminals of the second sensor; means (M3) for comparing the first voltage and the second voltage in order to detect the approach of the portable apparatus coming from outside or coming from inside the vehicle

A Smart Sensing Architecture for Misalignment Measurements

Abstract: Smart sensing architectures based on inductive readout are very intriguing solutions to perform measurements in industrial and in general in harsh environments. The proposed system is based on a primary coil as fixed sensing element and in front of it, a movable and battery less receiving sensor coil. The architecture measures the misalignment, with a non-destructive approach, between two objects and offers a high flexibility to perform the measurements also in presence of humidity, dirtiness, debris, oils or other non-homogeneous surfaces. Furthermore, it is easy to be implemented at low cost and it presents a wide operative range. For data acquisition, a low energy Bluetooth board is used, which starts automatically as soon as a minimum voltage value is reached. The system has been designed and studied; a laboratory prototype has been realized and experimentally validated. The results demonstrate the suitability of the proposed method.