IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-06-22DOI: 10.1109/LSENS.2026.3705902
Abhinay Dubey;Indu Kant Dwivedi;Shweta Tripathi
{"title":"Enzymatic Glucose Sensing Using Glucose Oxidase-Integrated Conducting Polymer Extended Gate Field Effect Transistor","authors":"Abhinay Dubey;Indu Kant Dwivedi;Shweta Tripathi","doi":"10.1109/LSENS.2026.3705902","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3705902","url":null,"abstract":"This letter presents a glucose-sensing device that detects changes in glucose concentrations. The detection is based on the diffusion of protons, generated by the enzymatic oxidation of glucose at the surface of a glucose oxidase (Gox) thin film, which continuously affects the drain current. The Gox sensing membrane is fabricated by depositing Gox onto a chitosan which is deposited on Poly-TPD (Poly[bis(4-phenyl) (4-butylphenyl) amine]) using a simple, cost-effective spin-coating technique onto an indium tin oxide-coated substrate. The ion interaction at the Gox surface is integrated with an extended-gate field-effect transistor architecture—an innovative approach in this work. A linear increase in the drain current was observed with rising glucose concentration, demonstrating that the reported organic thin film transistor (OTFT)-based glucose sensor retains enzyme bioactivity and can be applied as a reliable glucose biosensor.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"3504604-3504604"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sleep Posture Recognition for Dual-Occupancy Using Thermal Sensor Arrays","authors":"Selwan Abdussalam;Abdallah Naser;Ahmad Lotfi;Salisu Yahaya","doi":"10.1109/LSENS.2026.3709690","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3709690","url":null,"abstract":"This letter details our proposed approach and results for nonintrusive sleep posture recognition in real home environments using a thermal sensor array. While existing studies focus only on a single user and ignore shared bedding, we propose a 16-state coupled joint-posture matrix for dual occupancy. By framing an enhanced EfficientNet-B0 architecture as a virtual sensor enhancement, squeeze-and-excitation modules are implemented to perform adaptive channelwise recalibration. This acts as a nonlinear filter to prioritize subject-specific thermal gradients while suppressing surrounding environmental noise. Our results from 12 000 thermal frames indicate a classification accuracy of 90.9%. The system demonstrates high spatial invariance to subject displacement and robust generalizability across diverse body mass index ranges, offering a privacy-preserving solution for long-term health monitoring.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"2503904-2503904"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-07-06DOI: 10.1109/LSENS.2026.3710573
Zihan Lu;Hongxin Xu;Xuefei Yan;Huahuang Luo;Yuan Wang;Qingqing Ke
{"title":"A Dual-Top-Electrode ScAlN-Based Piezoelectric Micromachined Ultrasound Transducer With Series-Connected Electrode Topology for Enhanced Receiving Sensitivity","authors":"Zihan Lu;Hongxin Xu;Xuefei Yan;Huahuang Luo;Yuan Wang;Qingqing Ke","doi":"10.1109/LSENS.2026.3710573","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3710573","url":null,"abstract":"This letter presents a dual-top-electrode scandium aluminum nitride (ScAlN)-based piezoelectric micromachined ultrasonic transducer (PMUT) operating in the series-connected electrode (SCE) topology. In the transmitting mode, the SCE topology ideally halves the local voltage across each piezoelectric unit. This allows a higher external drive voltage for the same electric field constraint, potentially doubling the maximum displacement. For the receiving mode, the SCE topology yields an excellent receiving sensitivity of 5.71 mV/Pa, which is 1.58 times that of its conventional outer-floating electrode (OFE) topology. The enhancement of receiving sensitivity is attributed to the reduction in static capacitance by series connection. Due to the slightly reduced transmitted sound pressure and substantially enhanced receiving sensitivity, the pulse-echo signal captured in the SCE transmit–receive configuration exhibits a 51.8% improvement over the OFE-based scheme. The PMUT with SCE is believed to reveal significant potential for highly sensitive ranging applications.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"2504204-2504204"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148628003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-07-14DOI: 10.1109/LSENS.2026.3713253
Nusrat Praween;Sunil Kumar;Palash Kumar Basu
{"title":"Label-Free Electrochemical Detection of Mucin in Urinary Extracellular Vesicles to Monitor High-Altitude Hypoxia Adaptation","authors":"Nusrat Praween;Sunil Kumar;Palash Kumar Basu","doi":"10.1109/LSENS.2026.3713253","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3713253","url":null,"abstract":"Severe hypoxic conditions cause systemic physiological stress, highlighting the need for noninvasive health monitoring. Urinary extracellular vesicles (uEVs) contain stable, hypoxia-responsive biomarkers like Mucin-1 (MUC1) and Mucin-5AC (MUC5AC). We introduce a compact, label-free electrochemical impedance spectroscopy biosensor with reagent-free electric field lysis method. A 30-s square wave (50 mV, 1 kHz) applied directly to urine quickly breaks down uEV lipid membranes, releasing intravesicular contents efficiently. Validated with enzyme-linked immunosorbent assay (ELISA), this physical on-chip lysis yields a 3.06-fold increase in biomarker recovery compared to untreated samples without denaturing chemicals. The sensor was tested with urine samples taken before and after a 10-day high-altitude (14 860 ft) hypoxic challenge. The dual-biomarker system detected significant, individual increases posthypoxia, ranging from 54.7% to 526.1% for EV-MUC5AC and 60.9% to 127.4% for EV-MUC1. By bypassing traditional isolation and extraction processes, this platform reduces workflow time by about 95%, offering a rapid, highly sensitive point-of-care method for real-time monitoring of physiological stress in extreme environments.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"4502804-4502804"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-06-29DOI: 10.1109/LSENS.2026.3708157
Jianjun Ma;Bin Zhou;Qi Wei;Rong Zhang
{"title":"Analysis and Closed-Loop Suppression of In-Plane Linear Acceleration Sensitivity for MEMS Quadruple Mass Gyroscope","authors":"Jianjun Ma;Bin Zhou;Qi Wei;Rong Zhang","doi":"10.1109/LSENS.2026.3708157","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3708157","url":null,"abstract":"This letter presents theoretical analysis, closed-loop suppression design, and experimental verification of in-plane linear acceleration sensitivity in a center-anchor-supported quadruple-mass gyroscope (CSQMG). Despite the inherent common-mode rejection of multimass structures, capacitive nonlinearity, and coupling electrostatic forces remain significant sources of g-sensitivity errors. A theoretical model considering capacitive nonlinearity in the sense electrodes and coupling electrostatic forces along the sense direction in the drive electrodes is developed for the CSQMG. Dedicated electrodes featuring a 45°-tilted comb design are implemented to suppress acceleration-induced displacement in a closed-loop feedback system. Experimental results demonstrate that the bias g-sensitivity is substantially reduced from 98.6°/h/g to 7.9°/h/g. Furthermore, scale factor g-sensitivity tests under centripetal acceleration show that the scale factor increment is suppressed from 0.27% to nearly zero. These results verify the effectiveness of the proposed closed-loop suppression technique for reducing MEMS gyroscope g-sensitivity, and further support the implementation of a novel single-drive six-axis integrated chip that combines a single-drive three-axis CSQMG and three-axis closed-loop accelerometers.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"2504004-2504004"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-07-16DOI: 10.1109/LSENS.2026.3713669
João Henrique Campos Soares;José Mario Nishihara de Albuquerque;Giovanni Braglia;André Eugênio Lazzaretti;André Schneider de Oliveira;Ronnier Frates Rohrich
{"title":"Machine Learning-Based Virtual Luxmeters for Fault Compensation and Angular Sensing Expansion in Robotic Lighting Inspection","authors":"João Henrique Campos Soares;José Mario Nishihara de Albuquerque;Giovanni Braglia;André Eugênio Lazzaretti;André Schneider de Oliveira;Ronnier Frates Rohrich","doi":"10.1109/LSENS.2026.3713669","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3713669","url":null,"abstract":"This letter proposes a machine learning-based virtual luxmeter framework for robotic lighting inspection systems, aiming to improve sensing robustness and expand angular measurement coverage without requiring additional hardware. Traditional robotic lighting inspection platforms rely exclusively on physical luxmeters, limiting angular resolution and making the system vulnerable to sensor failures or faulty readings. The proposed approach employs a multilayer perceptron model to learn the spatial correlations between multidirectional illuminance measurements and robot orientation, enabling both physical sensor reconstruction and virtual sensor generation. To support model training and validation, a controlled rotational acquisition methodology was developed using a seven-sensor robotic platform under fixed laboratory lighting conditions, generating ground-truth data for intermediate angular sensing. Experimental validation demonstrated high reconstruction accuracy for physical sensor replacement, achieving mean absolute errors below 1 lx, while virtual sensor inference achieved average errors of approximately 5 lx. Although this indoor Proof of Concept requires future retraining for complex outdoor deployment, the results validate the methodology’s capability to compensate faulty readings and generate reliable virtual estimations, increasing the sensing density and reliability of the framework.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"6007904-6007904"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148627804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-07-03DOI: 10.1109/LSENS.2026.3710058
Sadman Rahman;Rishi Raj Sharma;Kazi Newaj Faisal
{"title":"Radar-Based Sleep Posture Transition Sensing: An Efficient Deep Learning Hierarchical Temporal Architecture Utilizing Depthwise Convolution","authors":"Sadman Rahman;Rishi Raj Sharma;Kazi Newaj Faisal","doi":"10.1109/LSENS.2026.3710058","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3710058","url":null,"abstract":"Sleep posture transitions (SPTs) are critical indicators of sleep quality, essential for preventing posture-related complications in clinical and assistive care. Conventional vision-based, infrared, and pressure-mat monitoring systems face limitations in privacy preservation and robustness. This letter presents a sensor-oriented radar signal processing method for SPT recognition using frequency-modulated continuous-wave radar, processing time-range (TR) maps through a hierarchical temporal architecture. The proposed single-branch network employs depthwise convolutions, multihead self-attention, generalized mean pooling, and bidirectional recurrent modeling to extract discriminative features from radar-signal-derived TR representations. Evaluated on a seven-class SPT dataset with 1407 TR samples from 20 participants, the method achieves 99.29% accuracy under fivefold cross-validation. A subject-independent leave-one-subject-out evaluation further confirms strong generalization, with performance of 99.22% <inline-formula><tex-math>$pm$</tex-math></inline-formula> 1.78% across subjects. Robustness analysis under Gaussian noise perturbation maintains 98.94% accuracy, indicating resilience to signal degradation and environmental variations. Comparative analysis with time-Doppler maps with 1400 samples achieves 95.71% accuracy, demonstrating the superiority of range-based displacement representations over velocity-based signatures. The compact 18.6 M parameter architecture with 2.10 giga floating point operations per second and 5.787 ms inference time enables real-time deployment in privacy-preserving healthcare monitoring systems while maintaining sensor-level signal fidelity.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"6007504-6007504"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148628169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-06-29DOI: 10.1109/LSENS.2026.3708183
Mohammad Arif Khan;Sourav Roy;Kaushik Bandopadhyay;Avishek Adhikary
{"title":"Multicondition Crack Detection and Surface Assessment for Underwater Metal Structures Using Adaptive Vision Models","authors":"Mohammad Arif Khan;Sourav Roy;Kaushik Bandopadhyay;Avishek Adhikary","doi":"10.1109/LSENS.2026.3708183","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3708183","url":null,"abstract":"Ensuring the integrity of underwater metal structures requires precise crack detection in regular basis. Identifying the surface condition is also crucial because rusted areas necessitate specific prerepair treatments in case of crack maintenance. An accurate image-based crack detection and surface classification (rust or nonrust) directly from the image data collected from the camera mounted on an under remotely operating vehicle can bring a paradignm shift in underwater maintenance. However, such detection accuracy is heavily affected by water types, turbidity, or the presence of algae in water. In this work, we present a dual-task learning framework incorporating DenseNet201 for surface classification and a you only look once (YOLOv8) models for crack detection, trained under various types of water: clean, turbid, or algae-affected. With customized YOLOv8 models by optimizing confidence threshold as per water types, we have achieved precision = 87.4% and mAP@50 = 84.0 for clean water. Furthermore, by proposing an adaptive scheme for camera positioning based on water turbidity, the proposed framework achieve an average mAP@50 82.7% for water turbidity ranging from 15 to 120 nephelometric turbidity units (clean to turbid). The DenseNet201 model on the other hand shows an accuracy of 99.38% accuracy in detecting rust surface in all water.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"5505004-5505004"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IEEE Sensors LettersPub Date : 2026-08-01Epub Date: 2026-07-14DOI: 10.1109/LSENS.2026.3713275
Mao-Hsiu Hsu;Bo-Jie Zhang
{"title":"AI-Generated Fingerprint Forgery Detection for Tiny Partial Fingerprint Sensors Using Multigenerative Model Framework With Feature Augmentation","authors":"Mao-Hsiu Hsu;Bo-Jie Zhang","doi":"10.1109/LSENS.2026.3713275","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3713275","url":null,"abstract":"With the rapid advancement of generative AI, fingerprint sensing systems face increasing threats from sophisticated forgery attacks. This letter investigates AI-generated fingerprint forgeries for capacitive tiny partial fingerprint sensors using generative adversarial networks-based and diffusion-generated samples. We propose a generalized detection framework using a parallel binary classifier and multiclassifier architecture integrated with feature augmentation. Through multigenerative training, the proposed method captures subtle sensing artifacts from different generative models and improves generalization to unseen forgeries. Experimental results on the in-house sensor dataset achieve average accuracies of 88.57% under the single-generative model protocol and 92.62% under the multigenerative model protocol. Cross-dataset evaluations on NIST, FVC, and LivDet further achieve 94.90%, 93.91%, and 95.80%, respectively. This work supports effective fingerprint presentation attack detection for practical biometric sensing systems.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 8","pages":"6007704-6007704"},"PeriodicalIF":2.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}