Wireless Transducer Research Articles

Smart Wireless Transducer Dedicated for Use in Aviation Laboratories.

Reliable testing of aviation components depends on the quality and configuration flexibility of measurement systems. In a typical approach to test instrumentation, there are tens or hundreds of sensors on the test head and test facility, which are connected by wires to measurement cards in control cabinets. The preparation of wiring and the setup of measurement systems are laborious tasks requiring diligence. The use of smart wireless transducers allows for a new approach to test preparation by reducing the number of wires. Moreover, additional functionalities like data processing, alarm-level monitoring, compensation, or self-diagnosis could improve the functionality and accuracy of measurement systems. A combination of low power consumption, wireless communication, and wireless power transfer could speed up the test-rig instrumentation process and bring new test possibilities, e.g., long-term testing of moving or rotating components. This paper presents the design of a wireless smart transducer dedicated for use with sensors typical of aviation laboratories such as thermocouples, RTDs (Resistance Temperature Detectors), strain gauges, and voltage output integrated sensors. The following sections present various design requirements, proposed technical solutions, a study of battery and wireless power supply possibilities, assembly, and test results. All presented tests were carried out in the Components Test Laboratory located at the Łukasiewicz Research Network-Institute of Aviation.

Wireless portable transducer for nondestructive evaluation applications based on highly nonlinear solitary waves

A novel technique based on highly nonlinear solitary waves (HNSWs) has recently emerged to inspect / monitor engineering structures. The method is based on the actuation and detection of solitary waves propagating along a monoperiodic array of spherical particles, the last of which is in dry point contact with the material to be evaluated or monitored. The technique relies on the proved hypothesis that the dynamic interaction between the waves and the element to be inspected is dependent upon the mechanical properties and the integrity of the element. The method makes use of the so-called HNSW transducer, which consists of the array held within a rigid frame, an electromagnet that enables the excitation of the solitary waves through mechanical impact, and a sensor to detect the waves. The transducer is typically wired to a data acquisition system that controls the excitation and detection of the waves and stores the time series for post-processing. In the study presented in this paper, a portable, small wireless transducer was designed, assembled, and tested. The new instrument enables the characterization of small or soft samples without any wired connection to electronic test equipment. The reliability of the new device was proven by completing a comparative test in which the conventional wired and the novel wireless configuration were used to probe three samples made of different materials, namely steel, PDMS membrane, and Sawbones®. Then, the instrument was used to test the same membrane subjected to different pressures. The results of the experiments successfully proved that the instruments can accurately operate without the support of electronic equipment and can be used to identify subtle differences in soft materials.

Remote wireless monitoring of localized corrosion using compact solitary waves

This article presents a method to monitor corrosion remotely, based on highly nonlinear solitary waves, which are compact and nondispersive. In the study presented in this article, two types of solitary wave transducers were used to monitor accelerated localized corrosion on a steel plate. The first type consists of a chain of spherical particles surmounted by a commercial solenoid wired to, and controlled by, a data acquisition system used to lift and release the first particle of the chain and induce the mechanical impacts and stress waves in the chain. The chain included a piezoelectric wafer disk, also wired to the same data acquisition system, to sense, digitize, and store the propagating waves for post-processing. The second type of transducer was identical to the first one but the data acquisition system was replaced by a wireless node that communicated with a mobile device using a Bluetooth connection. Eight transducers were used to monitor the plate for over a week to detect the onset and progression of localized corrosion. Corrosion detection was performed by extracting a few features from the time waveforms and feeding these features to an outlier analysis algorithm based on the Mahalanobis distance. The results of the experiment showed the effectiveness of the proposed monitoring approach at detecting defects close to the transducers and confirm previous numerical predictions by the authors. The experiments also provided evidence that the performance of the wireless transducers is nearly identical to the performance of their wired counterparts, paving the way to a new paradigm for the structural health monitoring of remote structural components in harsh environments.

Detection and Classification of Corrosion-related Damage Using Solitary Waves

ABSTRACT This paper presents an inspection technique based on highly nonlinear solitary waves, wireless transducers, and machine learning. The technique was demonstrated on a plate subjected to accelerated corrosion while monitored with wired and wireless transducers, designed and assembled in laboratory. The tethered device consisted of a chain of spheres surmounted by a solenoid wired to and driven by a data acquisition system to control the first particle of the chain in order to induce the impact between the particle and the chain needed to generate the stress wave. The chain contained a piezoelectric wafer disk, also wired to the same data acquisition system, to sense the waves. The wireless transducers were identical to their wired counterparts, but the data acquisition system was replaced by a wireless node that communicated with a tablet via Bluetooth. Four wired and four wireless transducers were used to monitor the plate for nearly a week to detect the onset and progression of electrochemical corrosion. A few features were extracted from the time waveforms and then fed to a machine learning algorithm to classify damage. The results showed the effectiveness of the proposed approach at labeling defects close to the transducers.

Potentio-tunable FET sensor having a redox-polarizable single electrode for the implementation of a wearable, continuous multi-analyte monitoring device

The emerging field of wearable devices for monitoring bioanalytes calls for the miniaturization of biochemical sensors. The only commercially available electrochemical wearable monitoring medical devices for bioanalytes are the amperometric continuous glucose monitoring (CGM) systems. The use of such amperometric methods to monitor glucose levels requires a relatively large electrode surface area for sufficient redox species collection, allowing accurate measurements to be made. Consequently, miniaturization of such sensors bearing large electrodes is challenging. Furthermore, it is difficult to introduce and deploy more than one electrode–based sensor per device, thereby limiting the number of analytes that can be monitored in parallel. To address these limitations, we have employed a non-referenced, single polarizable electrode coupled to a fin-shaped field-effect transistor (Fin-FET). We have discovered that by passivating the FET area by a relatively thick oxide and/or polytetrafluoroethylene (PTFE) polymer, leaving only the polarizable working electrode (WE) exposed, we can monitor redox analytes at the micromolar to millimolar concentration range. We attribute this effect to the WE polarization by the solution redox species. We have exploited the superior sensitivity of the adjacent silicon-based Fin-FET to detect changes in sensor electrode potentials induced by the redox species. Furthermore, we demonstrated the correlation between a specific analyte and the biasing WE potential on the accumulation/depletion of the coupled Fin-FET channel as manifested by the transistor source-drain current. Moreover, we utilized the analyte-electrode potential interaction, which is analyte-specific, to tune the specificity of the sensor towards an analyte of choice. In addition, we demonstrated the use of a single-electrode potentiometric sweep to assist in identifying the accumulation/depletion as a result of analyte-WE state. Collectively, the tiny potentio-tunable electrochemical sensor (PTEchem sensor) area is ~50 × 50 µm, and dedicated wireless transducer facilitates the use of this sensor for wearable continuous, multi-metabolite monitoring.Graphical abstract

Performing central venous catheters in neonates and small infants undergoing cardiac surgery using a wireless transducer for ultrasound guidance: a prospective, observational pilot study

BackgroundNeonates and small infants with congenital cardiac disease undergoing cardiac surgery represent major challenges facing paediatric anaesthesia and perioperative medicine. Aims.We here aimed to investigate the success rates in performing ultrasound (US) guided central venous catheter insertion (CVC) in neonates and small infants undergoing cardiac surgery, and to evaluate the practicability and feasibility of thereby using a novel wireless US transducer (WUST).MethodsThirty neonates and small infants with a maximum body weight of 10 kg and need for CVC before cardiac surgery were included in this observational trial and were subdivided into two groups according to their weight: < 5 kg and ≥ 5 kg. Cannulation success, failure rate, essential procedure related time periods, and complications were recorded and the clinical utility of the WUST was assessed by a 5-point Likert scale.ResultsIn total, CVC-insertion was successful in 27 (90%) of the patients and the first attempt was successful in 24 (78%) of patients. Success rates of CVC were 80% < 5 kg and 100% ≥5 kg. Comparing the two groups we found a clear trend towards longer needle insertion time in patients weighing < 5 kg (33 [28–69] vs. 24 [15–37]s, P = .07), whereas, the total time for catheter insertion and the duration of the whole procedure were similar in both groups (199 [167–228] vs. 178 [138–234] and 720[538–818] vs. 660 [562–833]s. In total, we report 3 (10%) cases of local hematoma as procedure-related complications. Assessments of the WUST revealed very good survey results for all parameters of practicability and handling (all ratings between 4.5 and 5.0).ConclusionAlthough difficulties in CVC-placement seem to relate to vessel size and patient’s weight, US guided CVC-insertion represents a valuable, fast, and safe intervention in neonates and small children undergoing cardiac surgery. Using the WUST is feasible for this clinical application and may aid in efforts aiming to optimize perioperative care.Trial registrationWireless US-guided CVC placement in infants; Clinicaltrials.gov: NCT04597021; Date of Registration: 21October, 2020; retrospectively registered.

A Standard-Based Internet of Things Platform and Data Flow Modeling for Smart Environmental Monitoring

The environment consists of the interaction between the physical, biotic, and anthropic means. As this interaction is dynamic, environmental characteristics tend to change naturally over time, requiring continuous monitoring. In this scenario, the internet of things (IoT), together with traditional sensor networks, allows for the monitoring of various environmental aspects such as air, water, atmospheric, and soil conditions, and sending data to different users and remote applications. This paper proposes a Standard-based Internet of Things Platform and Data Flow Modeling for Smart Environmental Monitoring. The platform consists of an IoT network based on the IEEE 1451 standard which has the network capable application processor (NCAP) node (coordinator) and multiple wireless transducers interface module (WTIM) nodes. A WTIM node consists of one or more transducers, a data transfer interface and a processing unit. Thus, with the developed network, it is possible to collect environmental data at different points within a city landscape, to perform analysis of the communication distance between the WTIM nodes, and monitor the number of bytes transferred according to each network node. In addition, a dynamic model of data flow is proposed where the performance of the NCAP and WTIM nodes are described through state variables, relating directly to the information exchange dynamics between the communicating nodes in the mesh network. The modeling results showed stability in the network. Such stability means that the network has capacity of preserve its flow of information, for a long period of time, without loss frames or packets due to congestion.

Dynamic Bayesian Network-Based Escape Probability Estimation for Coach Fire Accidents

Coach emergency escape research is an effective measure to reduce casualties under serious vehicle fire accidents. A novel experiment method employing a wireless transducer was implemented and the head rotation speed, rotation moment and rotation duration were collected as the input variables for the classification and regression tree (CART) model. Based on this model, the classification result explicitly pointed out that the exit searching efficiency was evolving. By ignoring the last three unimportant factors from the Analytic Hierarchy Process (AHP), the ultimate Dynamic Bayesian Network (DBN) was built with the temporal part of the CART output and the time-independent part of the vehicle characteristics. Simulation showed that the most efficient exit searching period is the middle escape stage, which is 10 seconds after the emergency signal is triggered, and the escape probability clearly increases with the efficient exit searching. Furthermore, receiving emergency escape training contributes to a significant escape probability improvement of more than 10%. Compared with different failure modes, the emergency hammer layout and door reliability have a more significant influence on the escape probability improvement than aisle condition. Based on the simulation results, the escape probability will significantly drop below 0.55 if the emergency hammers, door, and aisle are all in a failure state.

A Flexi-PEGDA Upconversion Implant for Wireless Brain Photodynamic Therapy.

Near-infrared (NIR) activatable upconversion nanoparticles (UCNPs) enable wireless-based phototherapies by converting deep-tissue-penetrating NIR to visible light. UCNPs are therefore ideal as wireless transducers for photodynamic therapy (PDT) of deep-sited tumors. However, the retention of unsequestered UCNPs in tissue with minimal options for removal limits their clinical translation. To address this shortcoming, biocompatible UCNPs implants are developed to deliver upconversion photonic properties in a flexible, optical guide design. To enhance its translatability, the UCNPs implant is constructed with an FDA-approved poly(ethylene glycol) diacrylate (PEGDA) core clad with fluorinated ethylene propylene (FEP). The emission spectrum of the UCNPs implant can be tuned to overlap with the absorption spectra of the clinically relevant photosensitizer, 5-aminolevulinic acid (5-ALA). The UCNPs implant can wirelessly transmit upconverted visible light till 8 cm in length and in a bendable manner even when implanted underneath the skin or scalp. With this system, it is demonstrated that NIR-based chronic PDT is achievable in an untethered and noninvasive manner in a mouse xenograft glioblastoma multiforme (GBM) model. It is postulated that such encapsulated UCNPs implants represent a translational shift for wireless deep-tissue phototherapy by enabling sequestration of UCNPs without compromising wireless deep-tissue light delivery.

Embedded server to automatic control of wireless transducer network for irrigation based on Internet of things

The growth of the Internet of Things, as well as the optimization needs for agriculture, have opened many opportunities for projects with the integration of these two areas. This paper shows the development of a solution to monitoring crops using the Internet of Things. The sensors and actuators for this precision agriculture design are able to exchange data with an embedded server, which runs on an Intel Edison device. Therefore, an ad-hoc wireless sensor network is established among the devices, using the MQTT protocol. As a result, the monitoring and control of a watering crop project were possible using the proposed solution. In addition, the embedded server allowed the creation of a web interface for the farmer, which can interact with the whole system throughout a web browser. Keywords: Embedded server. Internet of things. Precision agriculture. Wireless sensor network.

On building a smarter ecosystem using the internet of intelligent things: progress and future challenges

With a growing interest in the Internet of Things (IoT), the businesses are undergoing a revolution in the way they monitor and control. In the recent past, many applications were developed using the IoT system architectures in various business verticals such as industrial, healthcare, farming, transportation, etc. However, with the development of low-complex artificial intelligence frameworks which are capable of operating on the edge devices, the IoT architectures have taken a major leap leading to the Internet of Intelligent Things (IoIT). In this paper, we discuss our focused research and applications of IoIT across the following verticals: (1) healthcare, (2) smart buildings, (3) farming, along with the recent state of the art methodologies and future challenges. Under the healthcare, we laid our main focus on the development of AI enabled computer-aided diagnosis framework, which acquires the scanning information from a wireless ultrasound transducer and automatically identifies the abnormalities present. Also, we developed a low-complex brain-controlled IoT environments framework which automatically classifies the motor imagery task performed by the user using 22 channel electroencephalography. Using IoIT, we developed a novel non-invasive technology capable of monitoring various electrical parameters without any need for cutting the wires. This developed non-invasive power monitor is capable of generating real-time alerts in the case of system malfunctions and will be a key enabler for smart buildings. Also, we developed mathematical, simulation, and experimental models for analyzing the performance of channel access mechanisms of dense traffic IoT networks.

Wireless Sensor Network for Temperatures Estimation in an Asynchronous Machine Using a Kalman Filter

&lt;p class="Abstract"&gt;A 4&lt;sup&gt;th&lt;/sup&gt;-order Kalman filter (KF) algorithm is developed based on the thermal model of an asynchronous machine. The thermal parameters are identified and KF is implemented in a wireless sensor network (WSN) to estimate the temperatures of the stator windings, the rotor cage, and the stator core of an asynchronous machine. The rotor speed, coolant air temperature, and the effective current and voltage are acquired by a WTIM (wireless transducer interface module) separately and transmitted to a NCAP (network capable application processor) where the KF algorithm is implemented. Losses of the stator windings and the rotor cage are copper losses, and the stator core losses are iron losses. The losses of the stator windings, the rotor cage and the stator core are calculated from the measurements and are processed with the coolant air temperature by KF. As the resistance varies from temperature, the estimated temperature of the stator windings is used for compensating the rising of resistance. Simulations and experiments on the test bench were performed before the KF algorithm is implemented on a wireless sensor node. The real-time temperature estimator on WSN is independent of control algorithm and can work under any load condition with very high accuracy.&lt;/p&gt;

Acoustic Transducers as Passive Cooperative Targets for Wireless Sensing of the Sub-Surface World: Challenges of Probing with Ground Penetrating RADAR.

Passive wireless transducers are used as sensors, probed by a RADAR system. A simple way to separate the returning signal from the clutter is to delay the response, so that the clutter decays before the echoes are received. This can be achieved by introducing a fixed delay in the sensor design. Acoustic wave transducers are ideally suited as cooperative targets for passive, wireless sensing. The incoming electromagnetic pulse is converted into an acoustic wave, propagated on the sensor substrate surface, and reflected as an electromagnetic echo. According to a known law, the acoustic wave propagation velocity depends on the physical quantity under investigation, which is then measured as an echo delay. Both conversions between electromagnetic and acoustic waves are based on the piezoelectric property of the substrate of which the sensor is made. Investigating underground sensing, we address the problems of using GPR (Ground-Penetrating RADAR) for probing cooperative targets. The GPR is a good candidate for this application because it provides an electromagnetic source and receiver, as well as echo recording tools. Instead of designing dedicated electronics, we choose a commercially available, reliable and rugged instrument. The measurement range depends on parameters like antenna radiation pattern, radio spectrum matching between GPR and the target, antenna-sensor impedance matching and the transfer function of the target. We demonstrate measurements at depths ranging from centimeters to circa 1 m in a sandbox. In our application, clutter rejection requires delays between the emitted pulse and echoes to be longer than in the regular use of the GPR for geophysical measurements. This delay, and the accuracy needed for sensing, challenge the GPR internal time base. In the GPR units we used, the drift turns out to be incompatible with the targeted application. The available documentation of other models and brands suggests that this is a rather general limitation. We solved the problem by replacing the analog ramp generator defining the time base with a fully digital solution, whose time accuracy and stability relies on a quartz oscillator. The resulting stability is acceptable for sub-surface cooperative sensor measurement.

Flexible architecture of data acquisition firmware based on multi-behaviors finite state machine.

A flexible firmware architecture for different kinds of data acquisition systems, ranging from high-precision bench instruments to low-cost wireless transducers networks, is presented. The key component is a multi-behaviors finite state machine, easily configurable to both low- and high-performance requirements, to diverse operating systems, as well as to on-line and batch measurement algorithms. The proposed solution was validated experimentally on three case studies with data acquisition architectures: (i) concentrated, in a high-precision instrument for magnetic measurements at CERN, (ii) decentralized, for telemedicine remote monitoring of patients at home, and (iii) distributed, for remote monitoring of building's energy loss.

Development of wireless vibration transducer based on MEMS accelerometer

When monitoring the vibration of heavy rotating machinery, one often has problems with cables of vibration transducers, as those cables are usually long, heavy and prone to damage. This paper is focused on the development of a wireless vibration transducer, based on the MEMS accelerometer, which is free of those problems. Owing to the schematics proposed, developed sensor’s power consumption is low, at that analog filtering of vibration acceleration signal is provided. In the paper, spectral analysis based method of frequency response correction is also proposed. That method can be used for measurement of the vibration RMS and power spectra, while using an MCU with low computational power for data processing. The results of the tests conducted show that the transducer developed is well-behaved and that its precision is comparable to one of industrial piezoelectric transducers. So, the transducer developed can be used instead of the industrial transducers mentioned; at that, moving of the machine condition detection process from the high–level system to the transducer level allows one to decrease network traffic and simplify monitoring system as a whole.

Reliable Wireless Sensor Protocol Based Health Monitoring System

The patient monitoring during normal activity is getting more and more significant as a standard method to prevent craniology process for detection of transient ischemiaperiod ，cardiac arrhythmias as well as silent myocardium ischemic. In this paper, we mainly focus on the structureand the composition of awireless (600m) synchronizationarrhythmias invigilator as well as a alarming device for patients. To realize the corresponding functions, a Wireless Transducer Protocol (WTP) based on Time Divisibility Double (TDD) is what we require, the implemented system is totally composed of four main nodes includingthe Core (dominant) node which is a personal computer-based Graphic user system. It works at anstable frequency of 915MHz. The passive node is a digital signal processor-based board connected with the patients whichcould receive two channels of full-spectrum ECG signal at the same time, and uploads processed data at a specificperiod to the core node. The MPC8260 communications and the computeris composed of the dominant nodedesigned to receive data, decompress, and analyze the latest data baggage. The SRWF-501F915 completednoderealize the data communication.

Development of Wireless Transducer for Real-Time Remote Patient Monitoring

A novel wireless transducer that uses analog-based technology at 2.4 GHz is presented in this letter. The transducer consists of an electrocardiography (ECG) detection circuit and a novel three-stage amplitude modulation transmitter that up-converts the ECG signal to a 2.4-GHz carrier frequency. To minimize the effects due to local oscillator leakage as well as the interference at the image frequency, the intermediate frequency is carefully selected, and a bandpass filter with a very sharp selectivity is designed. As demonstrated by the experimental results, the full-wave ECG signals can be successfully demodulated from the transmitted signal using the presented transducer. This enables the possibility of using analog-based technology for remote patient monitoring in real time.

Wireless Ultrasound-Guided Axillary Vein Cannulation for the Implantation of Cardiovascular Implantable Electric Devices.

Ultrasound guidance for vascular cannulation seems safer and more effective than an anatomical landmark approach, though it has not gained widespread support partly due to workflow interference of wired probes. A wireless ultrasound transducer (WUST) may overcome this issue. We report the effectiveness, time consumption, and safety of the first-in-human experience in axillary vein cannulation guided with a novel WUST for the implantation of cardiovascular implantable electric devices (CIEDs). After a one-month training period, we routinely performed WUST-guided puncture to all first implants, prospectively registering data from the first 50 patients. We analyzed the time needed for preparing the WUST and for achieving each vein cannulation, and the rate of unsuccessful or accidental arterial punctures and complications. WUST-guided axillary vein access was successful in 49 out of 50 patients, totaling 86 cannulated veins. Median WUST preparation time was 55 [44-62] seconds and median time needed for each venous cannulation was 56 [36-71] seconds. A total of 84.9% of the veins were cannulated at the first attempt. There were 7 unsuccessful puncture attempts and 1 accidental arterial puncture. No pneumothorax, hemothorax, or nervous injury occurred in the 49 successfully cannulated patients. The unsuccessful one (distal subclavian occlusion) developed a minor local subcutaneous emphysema with no confirmed radiologic pneumothorax, not requiring intervention. During a follow-up of 2.5 ± 1.1 months, a patient developed a pocket infection, with no other significant complications. Ultrasound-guided axillary vein cannulation using a wireless transducer for the implantation of CIEDs is a feasible, fast, and safe method.

TEDS Extensions Toward Energy Management of Wireless Transducers

Energy and power management is one of the crucial tasks in any wireless transducers application. Therefore, wireless transducers often have application specific designs in order to optimize the energy management. However, this limits reuse of devices and causes much configuration effort. In this paper, we propose to map energy-related parameters of wireless transducers into a transducer electronic datasheet (TEDS). Thus, appropriate performance and power settings can be made for each application and the wireless transducers are easily adapted for a certain task. We show energy management is not just important for communication but also to the data acquisition or actuation submodules. Thus, our approach can also be used to consider the capabilities of submodules that are not related to communication. Despite versatile applicability, the structure of the TEDS remains comparatively simple.

A framework for wireless sensor networks management for precision viticulture and agriculture based on IEEE 1451 standard

Precision viticulture (PV) and precision agriculture (PA) requires the acquisition and processing of a vast collection of data coming typically from large scale and heterogeneous sensor networks. Unfortunately, sensor integration is far from being simple due to the number of incompatible network specifications and platforms. The adoption of a common, standard communication interface would allow the engineer to abstract the relation between the sensor and the network. This would reduce the development efforts and emerge as an important step towards the adoption of “plug-and-play” technology in PA/PV sensor networks. This paper explores this need and introduces a framework for smart data acquisition in PA/PV that relies on the IEEE 1451 family of standards, which addresses the transducer-to-network interoperability issues. The framework includes a ZigBee end device (sMPWiNodeZ), as an IEEE 1451 WTIM (Wireless Transducer Interface Module), and an IEEE 1451 NCAP (Network Capable Application Processor) that acts as gateway to an information service provider and WSN (Wireless Sensor Network) coordinator. The paper discusses the proposed IEEE 1451 system architecture and its benefits in PA/PV and closes with results/lessons learned from in-field trials towards smarter WSN.