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Highlights Recent developments of advanced electronic and optoelectronic gas sensors are introduced. Sensor array with artificial intelligence algorithms and smart gas sensors in “Internet of Things” paradigm are highlighted. Applications of smart gas sensors in environmental monitoring, medical and healthcare applications, food quality control, and public safety are described. Gas sensor is an indispensable part of modern society with wide applications in environmental monitoring, healthcare, food industry, public safety, etc. With the development of sensor technology, wireless communication, smart monitoring terminal, cloud storage/computing technology, and artificial intelligence, smart gas sensors represent the future of gas sensing due to their merits of real-time multifunctional monitoring, early warning function, and intelligent and automated feature. Various electronic and optoelectronic gas sensors have been developed for high-performance smart gas analysis. With the development of smart terminals and the maturity of integrated technology, flexible and wearable gas sensors play an increasing role in gas analysis. This review highlights recent advances of smart gas sensors in diverse applications. The structural components and fundamental principles of electronic and optoelectronic gas sensors are described, and flexible and wearable gas sensor devices are highlighted. Moreover, sensor array with artificial intelligence algorithms and smart gas sensors in “Internet of Things” paradigm are introduced. Finally, the challenges and perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.

The purpose of this work is the authors’ attempt to identify the main phases of information transformation in measurement channels on the example of an optical measurement channel with microprocessor control. The authors include such phases: hardware implementation and analytical representation of an optical sensor’s converting functions and a current-to-voltage converter; based on the methods of experimental computer science, the converting functions and sensitivity are deduced, analytical dependences for estimation of a range of measurement are obtained. It is shown that the choice of information transmission type in the microprocessor measuring channel significantly affects the speed of the measuring channel. Based on the uncertainty in the form of entropy before and after measurements, the amount of information for measuring channels with optoelectronic sensors is estimated. The application of the results obtained in the work allows even at the design stage of physical and mathematical modeling to assess the basic static metrological characteristics of measuring channels, aimed at reducing the stage of development and debugging of hardware and software and standardization of their metrological characteristics.

The vapour pressure of most explosives is very low. Therefore, the explosive trace detection is very difficult. To overcome the problem, concentration units can be applied. At the Institute of Optoelectronics MUT, an explosive vapour concentration and decomposition unit to operate with an optoelectronic sensor of nitrogen dioxide has been developed. This unit provides an adsorption of explosive vapours from the analysed air and then their thermal decomposition. The thermal decomposition is mainly a chemical reaction, which consists in breaking up compounds into two or more simple compounds or elements. During the heating process most explosive particles, based on nitro aromatics and alkyl nitrate, release NO2 molecules and other products of pyrolysis. In this paper, the most common methods for the NO2 detection were presented. Also, an application of the concentration and decomposition unit in the NO2 optoelectronic sensor has been discussed.

With robotic-assisted minimally invasive surgery (RAMIS), patients and surgeons benefit from a reduced incision size and dexterous instruments. However, current robotic surgery platforms lack haptic feedback, which is an essential element of safe operation. Moreover, teleportation control challenges make complex surgical tasks like suturing more time-consuming than those that use manual tools. This paper presents a new force-sensing instrument that semi-automates the suturing task and facilitates teleoperated robotic manipulation. In order to generate the ideal needle insertion trajectory and pass the needle through its curvature, the end-effector mechanism has a rotating degree of freedom. Impedance control was used to provide sensory information about needle–tissue interaction forces to the operator using an indirect force estimation approach based on data-based models. The operator’s motion commands were then regulated using a hyperplanar virtual fixture (VF) designed to maintain the desired distance between the end-effector and tissue surface while avoiding unwanted contact. To construct the geometry of the VF, an optoelectronic sensor-based approach was developed. Based on the experimental investigation of the hyperplane VF methodology, improved needle–tissue interaction force, manipulation accuracy, and task completion times were demonstrated. Finally, experimental validation of the trained force estimation models and the perceived interaction forces by the user was conducted using online data, demonstrating the potential of the developed approach in improving task performance.

Wearable robotic devices require sensors and algorithms that can recognize the user state in real-time, in order to provide synergistic action with the body. For devices intended for locomotion-related applications, shoe-embedded sensors are a common and convenient choice, potentially advantageous for performing gait assessment in real-world environments. In this work, we present the development of a pair of pressure-sensitive insoles based on optoelectronic sensors for the real-time estimation of temporal gait parameters. The new design makes use of a simplified sensor configuration that preserves the time accuracy of gait event detection relative to previous prototypes. The system has been assessed relatively to a commercial force plate recording the vertical component of the ground reaction force (vGRF) and the coordinate of the center of pressure along the so-called progression or antero-posterior plane (CoPAP) in ten healthy participants during ground-level walking at two speeds. The insoles showed overall median absolute errors (MAE) of 0.06 (0.02) s and 0.04 (0.02) s for heel-strike and toe-off recognition, respectively. Moreover, they enabled reasonably accurate estimations of the stance phase duration (2.02 (2.03) % error) and CoPAP profiles (Pearson correlation coefficient with force platform ρCoP = 0.96 (0.02)), whereas the correlation with vGRF measured by the force plate was lower than that obtained with the previous prototype (ρvGRF = 0.47 (0.20)). These results confirm the suitability of the insoles for online sensing purposes such as timely gait phase estimation and discrete event recognition.

Customized metasurfaces allow for controlling optical responses in photonic and optoelectronic devices over a broad band. For sensing applications, the spectral response of an optical device can be narrowed to a few nanometers, which enhances its capabilities to detect environmental changes that shift the spectral transmission or reflection. These nanophotonic elements are key for the new generation of plasmonic optical sensors with custom responses and custom modes of operation. In our design, the metallic top electrode of a hydrogenated amorphous silicon thin-film solar cell is combined with a metasurface fabricated as a hybrid dielectric multilayer grating. This arrangement generates a plasmonic resonance on top of the active layer of the cell, which enhances the optoelectronic response of the system over a very narrow spectral band. Then, the solar cell becomes a sensor with a response that is highly dependent on the optical properties of the medium on top of it. The maximum sensitivity and figure of merit (FOM) are SB = 36,707 (mA/W)/RIU and ≈167 RIU−1, respectively, for the 560 nm wavelength using TE polarization. The optical response and the high sensing performance of this device make it suitable for detecting very tiny changes in gas media. This is of great importance for monitoring air quality and thecomposition of gases in closed atmospheres.

This paper presents a multi-axis force/torque sensor based on simply-supported beam and optoelectronic technology. The sensor’s main advantages are: (1) Low power consumption; (2) low-level noise in comparison with conventional methods of force sensing (e.g., using strain gauges); (3) the ability to be embedded into different mechanical structures; (4) miniaturisation; (5) simple manufacture and customisation to fit a wide-range of robot systems; and (6) low-cost fabrication and assembly of sensor structure. For these reasons, the proposed multi-axis force/torque sensor can be used in a wide range of application areas including medical robotics, manufacturing, and areas involving human–robot interaction. This paper shows the application of our concept of a force/torque sensor to flexible continuum manipulators: A cylindrical MIS (Minimally Invasive Surgery) robot, and includes its design, fabrication, and evaluation tests.

Inaccurate oxygen saturation (SpO 2 ) measurements using photoplethysmography (PPG) based pulse oximeters on dark skin tones, were a direct cause of increased mortality during the Covid pandemic (2019-2022) and continue to negatively impact routine clinical monitoring. Inaccuracies are commonly interpreted as being caused by rich pigmentation in dark skin tones. A multispectral optoelectronic sensor (mSOS) with bespoke electronics has been created to overcome skin tone related difficulties of capturing peripheral blood pulsatile variations in deoxyhemoglobin (HHb) in red visible spectrum (>600 nm), and to improve the detection of oxyhaemoglobin (HbO 2 ) in infrared spectrum (>850 nm). The study demonstrates that a better understanding of the impact of skin tone on complex tissue optics is required to address pulse oximeter performance difficulties arising from skin pigmentation. The study evaluates the relationship between signal quality and skin tones with spectral illuminations at 515 nm, 601 nm, 631 nm and 940 nm. An approved hypoxia protocol with twelve subjects across three different skin tone groups (Individual Typology Angles (ITA): 50 ° - 41 ° , Monk Skin Tones: 2, 3 (Group I), ITA: 23 ° - 1 ° ; MST:4, 5 (Group II), and ITA: -31° - -66 ° , MST:8, 9 and 10 (Group III)) was implemented with the mSOS attached to the back of subject’s wrist, including six subjects of Group III. The results show the mSOS is capable of detecting peripheral blood perfusion variations with equivalent performance across three skin tone groups for all four wavelengths and throughout the oxygen desaturation range from 100% to 70%. Performance was maintained for all twelve subjects irrespective of skin tone as judged by signal to noise ratio (SNR) with the range of 19.19 - 25.00 and the standard deviation in the range of 1.42 - 5.60. Signal quality (SNR) remains consistently high across all the illumination wavelengths for all subjects, at all desaturation levels (100 - 70%). Upcoming studies will investigate SpO 2 calibration against SaO 2 gold standard reference with a larger subject cohort.

Infrared optoelectronic sensors have attracted considerable research interest over the past few decades due to their wide-ranging applications in military, healthcare, environmental monitoring, industrial inspection, and human–computer interaction systems. A comprehensive understanding of infrared optoelectronic sensors is of great importance for achieving their future optimization. This paper comprehensively reviews the recent advancements in infrared optoelectronic sensors. Firstly, their working mechanisms are elucidated. Then, the key metrics for evaluating an infrared optoelectronic sensor are introduced. Subsequently, an overview of promising materials and nanostructures for high-performance infrared optoelectronic sensors, along with the performances of state-of-the-art devices, is presented. Finally, the challenges facing infrared optoelectronic sensors are posed, and some perspectives for the optimization of infrared optoelectronic sensors are discussed, thereby paving the way for the development of future infrared optoelectronic sensors.