Photoelectric Sensor Research Articles

Contactless and short‐range vital signs detection with doppler radar millimetre‐wave (76–81 GHz) sensing firmware

AbstractVital signs such as heart rate (HR) and respiration rate (RR) are essential physiological parameters that are routinely used to monitor human health and bodily functions. They can be continuously monitored through contact or contactless measurements performed in the home or a hospital. In this study, a contactless Doppler radar W‐band sensing system was used for short‐range, contactless vital sign estimation. Frequency‐modulated continuous wave (FMCW) measurements were performed to reduce the influence of a patient's micromotion. Sensing software was developed that can process the received chirps to filter and extract heartbeat and breathing rhythm signals. The proposed contactless sensing system eliminates the need for the contact electrodes, electric patches, photoelectric sensors, and conductive wires used in typical physiological sensing methods. The system operates at 76–81 GHz in FMCW mode and can detect objects on the basis of changes in frequency and phase. The obtained signals are used to precisely monitor a patient's HR and RR with minimal noise interference. In a laboratory setting, the heartbeats and breathing rhythm signals of healthy young participants were measured, and their HR and RR were estimated through frequency‐ and time‐domain analyses. The experimental results confirmed the feasibility of the proposed W‐band mm‐wave radar for contactless and short‐range continuous detection of human vital signs.

Temperature-insensitive cascaded micro-ring resonator silicon photoelectric sensor based on wavelength interrogation for HSA detection

Silicon-based optical biosensors have garnered significant interest since their inception. They are, however, susceptible to temperature fluctuations in a controlled environment. In order to address this issue, we provide a solution including the utilization of a silicon-on-insulator (SOI) cascaded micro-ring resonators (CMRR) biosensor that is designed to be insensitive to temperature changes. It consists of two ring resonators exposed to the reference solution and analyte, respectively, their radius and waveguide width are designed to meet the temperature-insensitivity criterion of the CMRR sensor. The results of experiments indicate that by real-time monitoring of the envelope peak drift in the transmission spectrum of the sensor, the bulk refractive index (RI) sensitivity is 2940.71 nm/RIU, the limit of detection (LOD) is 3.1×10−5 RIU, and the temperature sensitivity is less than 40 pm/℃. Furthermore, the sensor was applied for HSA detection, with a calculated LOD of 18.09 ng/mL. The effect of temperature on HSA detection is much smaller than that of a CMRR sensor without athermal design. The sensor demonstrates high sensitivity and temperature insensitivity, and the absence of negative thermo-optic coefficient materials or supplementary temperature control mechanisms simplifies its practical applications. It can be made by a large array to detect different type protein molecules for high throughput multiparameter analysis.

The *.* Group’s Contribution to the Development of Technological Art in Brazil

Abstract The author describes three interactive installations presented by the *.* Group from the turn of the 1980s to the 1990s. The first installation, Fractal Art, explored the fractal theme through various mediums, including images, music, sculpture, video, and photoelectric sensors. The second installation, Foreseen Variations, featured a robot performing a choreography with a dancer in an environment equipped with a camera and TV sets, allowing the audience to be immersed in a virtual performance. The third installation, Aurora Beings, was a continuation of the previous one, where young people could program a choreography for the robot and act as both artists and engineers within the environment.

A Photoelectric Sensor Based on a Three-Layered Polyaniline@Graphene@Cadmium Sulfide Composite: Synthesis, Characterization and Study of Physicochemical Properties

A Photoelectric Sensor Based on a Three-Layered Polyaniline@Graphene@Cadmium Sulfide Composite: Synthesis, Characterization and Study of Physicochemical Properties

Design of Optical System for Ultra-Large Range Line-Sweep Spectral Confocal Displacement Sensor

The spectrum confocal displacement sensor is an innovative type of photoelectric sensor. The non-contact advantages of this method include the capacity to obtain highly accurate measurements without inflicting any harm as well as the ability to determine the object’s surface contour recovery by reconstructing the measurement data. Consequently, it has been widely used in the field of three-dimensional topographic measuring. The spectral confocal displacement sensor consists of a light source, a dispersive objective, and an imaging spectrometer. The scanning mode can be categorized into point scanning and line scanning. Point scanning is inherently present when the scanning efficiency is low, resulting in a slower measurement speed. Further improvements are necessary in the research on the line-scanning type. It is crucial to expand the measurement range of existing studies to overcome the limitations encountered during the detection process. The objective of this study is to overcome the constraints of the existing line-swept spectral confocal displacement sensor’s limited measuring range and lack of theoretical foundation for the entire system. This is accomplished by suggesting an appropriate approach for creating the optical design of the dispersive objective lens in the line-swept spectral confocal displacement sensor. Additionally, prism-grating beam splitting is employed to simulate and analyze the imaging spectrometer’s back end. The combination of a prism and a grating eliminates the spectral line bending that occurs in the imaging spectrometer. The results indicate that a complete optical pathway for the line-scanning spectral confocal displacement sensor has been built, achieving an axial resolution of 0.8 μm, a scanning line length of 24 mm, and a dispersion range of 3.9 mm. This sensor significantly expands the range of measurements and fills a previously unaddressed gap in the field of analyzing the current stage of line-scanning spectral confocal displacement sensors. This is a groundbreaking achievement for both the sensor itself and the field it operates in. The line-scanning spectral confocal displacement sensor’s design addresses a previously unmet need in systematic analysis by successfully obtaining a wide measuring range. This provides systematic theoretical backing for the advancement of the sensor, which has potential applications in the industrial detection of various ranges and complicated objects.

Thickness-dependent optoelectronic properties of titanium carbide MXene

Due to its tunable interlayer chemistry, MXene shows great potential in various sensor applications, but the optoelectronic properties of MXene are greatly hindered by the slow photoresponsivity of the intercalation chemistry. The main challenge to MXene in photoelectric sensor applications arises from its composite resistive properties. This paper analyzes the photoelectric responses separately by constructing singlelayer and multilayer structures. Under light, the resistance of a monolayer of MXene increases to 100.1% and recovers in 1 s. When the number of layers increases, the resistance of MXene quickly drops to 99.6% under light and recovers slowly within 15 s. In summary, this study reveals how MXene's layered structure affects its photoresponsivity, offering insights for advancing MXene-based optoelectronic sensors.

Photoelectric sensors constructed based on nanomaterials and their applications

Photoelectric sensors are electronic components that use the photoelectric effect to convert optical signals into electrical signals and are widely used in industrial automation, environmental monitoring, medical devices, and other fields. With continuous progress in fields such as information technology, material science, and manufacturing technology, optoelectronic sensor technology has developed rapidly. Nanomaterials have broad application prospects in optoelectronic sensors due to their unique properties. On the one hand, nanomaterials can enhance the electromagnetic field of light, leading to charge separation and enhanced electron transport, thereby achieving higher photoelectric conversion efficiency. On the other hand, nanomaterials have a larger specific surface area and higher light absorption and photosensitivity. In addition, due to the small size of nanomaterials, their surface energy has a greater impact and their response to the environment is more sensitive. This makes optoelectronic sensors based on nanomaterials a current research hotspot. Therefore, this article mainly introduces photoelectric sensors constructed using nanomaterials and their applications. This article first introduces various optoelectronic sensors made of nanomaterials, including inorganic semiconductors, organic photovoltaic materials, and two-dimensional materials. In addition, its applications in food safety, environmental monitoring, and medical fields were emphasized. It has reference significance for the development of future photoelectric sensors.

Bandgap regulation and doping modification of Ga2-x Cr x Se3 nanosheets.

Ga2Se3, an important direct wide bandgap semiconductor with excellent optoelectronic properties, has wide application potential in the fields of photodetectors, photoelectric sensors and solar cells. Herein, we describe the synthesis of Ga2Se3 semiconductor nanoparticles using a high temperature organic liquid phase method. Post-annealing treatment at different temperatures can not only improve the crystallinity of Ga2Se3 nanoparticles, but also regulate its optical band gap ranging from 2.50 to 2.80 eV. We further synthesized Ga2-x Cr x Se3 nanosheets by doping CrCl3·6H2O in the reaction process. By adjusting the Cr doping concentration, Ga2-x Cr x Se3 nanosheets can achieve a continuously tunable band gap in the range of 2.23 eV to 2.42 eV. Both Ga2-x Cr x Se3 nanosheets and Ga2Se3 nanoparticles exhibit excellent and stable photoelectric switching performance. With Cr doping, Ga2-x Cr x Se3 exhibits reduced Nyquist impedance and enhanced electrocatalytic activity, which is attributed to its ultrathin nanosheet morphology and large specific surface area. In addition, the diamagnetic behavior of pure Ga2Se3 changes to ferromagnetism with different Cr doping concentrations, and its magnetization is as high as 18.0 emu g-1 at x = 0.4. These findings demonstrate that Ga2-x Cr x Se3 nanosheets have significant potential in future optoelectronic and magnetoelectric applications.

Carbon-based photoelectrochemical sensors: recent developments and future prospects.

Owing to the considerable potential of photoelectrochemical (PEC) sensors, they have gained significant attention in the analysis of biological, environmental, and food markers. However, the limited charge mass transfer efficiency and rapid recombination of electron hole pairs have become obstacles in the development of PEC sensors. In this case, considering the unique advantages of carbon-based materials, they can be used as photosensitizers, supporting materials and conductive substrates and coupled with semiconductors to prepare composite materials, solving the above problems. In addition, there are many types of carbon materials, which can have semiconductor properties and form heterojunctions after coupling with semiconductors, effectively promoting the separation of electron hole pairs. Herein, we aimed to provide a comprehensive analysis of reports on carbon-based PEC sensors by introducing their research and application status and discussing future development trends in this field. In particular, the types and performance improvement strategies of carbon-based electrodes and the working principles of carbon-based PEC sensors are explained. Furthermore, the applications of carbon-based photoelectric sensors in environmental monitoring, biomedicine, and food detection are highlighted. Finally, the current limitations in the research on carbon-based PEC sensors are emphasized and the need to enhance the sensitivity and selectivity through material modification, structural design, improved device performance, and other strategies are emphasized.

Recent Advances in Nanowire-Based Wearable Physical Sensors.

Wearable electronics is a technology that closely integrates electronic devices with the human body or clothing, which can realize human-computer interaction, health monitoring, smart medical, and other functions. Wearable physical sensors are an important part of wearable electronics. They can sense various physical signals from the human body or the surrounding environment and convert them into electrical signals for processing and analysis. Nanowires (NW) have unique properties such as a high surface-to-volume ratio, high flexibility, high carrier mobility, a tunable bandgap, a large piezoresistive coefficient, and a strong light-matter interaction. They are one of the ideal candidates for the fabrication of wearable physical sensors with high sensitivity, fast response, and low power consumption. In this review, we summarize recent advances in various types of NW-based wearable physical sensors, specifically including mechanical, photoelectric, temperature, and multifunctional sensors. The discussion revolves around the structural design, sensing mechanisms, manufacture, and practical applications of these sensors, highlighting the positive role that NWs play in the sensing process. Finally, we present the conclusions with perspectives on current challenges and future opportunities in this field.

Research on temperature compensation method for photoelectric sensors

In order to make the temperature error of fiber-optic current sensor (FGB) based on polarization modulation principle meet the requirements of engineering applications, the temperature error characteristics of FGB are analyzed theoretically, and the optimized BP neural network is used for the temperature compensation of FGB, which realizes the nonlinear temperature error correction of the sensor, and compares and analyzes the experimental results with those of other types of temperature compensation algorithms. The results show that the temperature compensation results based on the neural network algorithm are better than other compensation effects. Finally, the repeatability of the FGB was experimentally verified using its full temperature experiment, and the temperature errors of the FGB in the range of 20 ℃~ 100 ℃ were less than 0.5% after the correction of the neural network algorithm.

Deflection Basin Detection of Pavements Based on Linear Array Charge-Coupled Device (CCD) Photoelectric Sensors

Deflection is an important indicator of the overall pavement strength, and it is generally detected using the Falling Weight Deflectometer (FWD). In response to the shortcomings of FWD in use, a pavement deflection detection method based on a linear array charge-coupled device (CCD) photoelectric displacement sensor is proposed. Firstly, a detailed description is given of the working principle of the deflection detection photoelectric sensor for the center point of the deflection basin and other points. Secondly, a photoelectric displacement sensor using linear array CCD deflection detection is designed, including a laser, CCD signal processing module, CCD and its driver module, and upper computer communication module. Among them, the EPF10K20TC144-4 device of the FLEX 10K series from ALTERA company is used to generate CCD driving pulses; Two DM54LS245 are selected as the driving interface for CCD photoelectric sensors, and corresponding filtering and signal amplification circuits are designed to address the noise problem of CCD photoelectric signal injection. Finally, the fixed threshold method separates the background and image signals in the CCD photoelectric signal, and the microcontroller is connected to the serial port of the upper computer through the MAX232 chip. The displacement measurement experiment uses the designed linear array CCD photoelectric displacement sensor. The results show that the road deflection basin detection method by the linear array CCD photoelectric displacement sensor fully meets the actual detection requirements and can obtain dynamic deformation information of the tested road surface. It is helpful for a detailed understanding of the changes in the deflection basin of the road surface under load.

Application of High-Speed Optical Measurement Based on Nanoscale Photoelectric Sensing Technology in the Optimization of Football Shooting Mechanics

This study introduces a novel application of nanoscale photoelectric sensing technology in the realm of football shooting mechanics, marking a significant advancement in the field of dynamic mechanical analysis. Traditional sensor analysis tools frequently struggle with attaining the necessary spatial and temporal resolution to detect subtle variations in dynamic mechanical actions, often leading to inaccuracies in complex movement analyses. Our research employs nanoscale photoelectric sensors to overcome these limitations, offering a ground breaking method for understanding and enhancing dynamic mechanical properties. These sensors detect minute changes in light signals correlated with mechanical movements, accurately depicting position, velocity, and acceleration through light intensity, wavelength, and phase data. To ensure the utmost data quality, the collected optical signal data undergoes extensive preprocessing, including median filtering. By implementing a three-dimensional (3D) coordinate system specifically designed for the mechanical system under study, this approach achieves a remarkable average root mean square error (RMSE) of 0.002, emphasizing the technology’s precision in measuring and optimizing dynamic mechanical processes. This research highlights the broad applicability of nanoscale photoelectric sensing technology in fields requiring high-precision mechanical analysis.

Zinc phthalocyanine compound-based photo-electric organic shock-proof disposable flexible sensors

This research study introduces a multifunctional photo-electric sensor that utilises a semiconductor composite material and is implemented on a cellulose substrate. The flex electronic devices were manufactured using a rubbing-in technique that does not require energy. The investigation focused on using a compound consisting of zinc phthalocyanine and multi-walled carbon nanotubes (MWCNTs) as an active layer. However, aluminium top electrodes were utilized for photo-electric characterization, respectively. The surface type symmetry was designed to achieve disposable organic, shock-proof, and vibration-free electronic devices. They are then analyzed and characterized for their morphological and electrical parameters. The material structural analysis was performed with x-ray diffraction of materials, UV–Vis, photo luminance, Fourier-transform infrared spectroscopy, and for electrical characterization, the capacitance and impedance at varying ultra-violet (0–1300 W/cm), infrared (0–1580 W/m2), and frequency (0.1–200 kHz) were performed. Each parameter's influence is broken out in detail to illuminate the underlying physics of the results further. The results show that when Infrared intensity rises, impedance falls, whereas UV intensity increases. In the context of capacitance, it is observed that exposure to ultraviolet radiation leads to a decrease or increase in capacitance, while intensification of infrared light also results in a corresponding change in capacitance.Moreover, it can be observed that the sensitivity of electronic equipment exhibits a reduction when the frequency is increased. These devices have a wide range of applications, such as their use in food supply chains to safeguard food from the detrimental impact of high ultraviolet and infrared radiation on public health. They can also be employed in the medical industry for optical physiotherapy treatments and in universities for research purposes in countries that fall below the international poverty line, owing to their cost-effective fabrication technique.

Development of a DC Motor Speed Control System Based on PID

In the field of motion control systems, motor speed control plays a pivotal role. Various control algorithms and methods have been developed for this purpose, and one of the earliest strategies to emerge was analog control. Over time, it has evolved into a typical control structure with convenient parameter tuning capable of meeting general control requirements. This design is based on digital control algorithms, with the ST89C52 microcontroller as the control core. It generates pulse-width modulation (PWM) pulses controlled by a digital algorithm to regulate the speed of direct circuit (DC) motors. Additionally, it utilizes a photoelectric sensor to convert motor speed into pulse frequency, which is fed back to the microcontroller, thereby achieving closed-loop speed control and eliminating static speed errors.

Solar Radiation Tracking Design Based on Photoelectric Sensor for Tracing Signal Reconstruction Algorithm

Due to the high precision, low power requirements, and maintenance-free nature, the four-quadrant photoelectric sensor (FQPS) and the laser displacement sensor are employed in the development of the two-axis solar tracker. Among them, when designing the optical path of the FQPS, a cavity-wandering optical path is introduced to control the spot size of the direct sunlight falling on the sensor. The sensor interface has five data transmission lines, of which four positive poles correspond to the four quadrants of the planar two-dimensional coordinate system. AD7793 is used as the signal collector and a differential amplifier with small clutter is integrated. A laser displacement sensor is installed in the solar radiation tracker to realize the self-correction of movement error. The main control circuit adopts DSP chip TMS320F28335 for the whole dual-axis sun tracker. In the experiment, Code Composer Studio was used for development, and SPA algorithm was used to measure the position. A number of error correction variables, such as year, month, day, time, minute, second, ΔT, time zone, longitude, latitude, etc., are added to the algorithm. After debugging the hardware and software, the sunrise and sunset times of a certain place on the solar terms such as spring equinox, summer solstice, autumn equinox and winter solstice in 2022 are tested, and compared with those released by the Meteorological Bureau. The tracking signal is rebuilt using proximal gradient descent technology. The results demonstrate that the signal-to-noise ratio under the reconstruction algorithm is continuously enhanced and tends to stabilize with an increase in sampling rate without noise, and it exhibits good signal reconstruction performance in the presence of noise and growing noise.

Analysis of Cargo Sorting Robot Based on Multiple Photoelectric Sensors

With the rise of e-commerce, dangerous goods such as flammable and explosives carried in logistics goods have a negative impact on the development of the logistics industry and seriously threaten staff safety. Infrared is widely used in the logistics cargo security inspection system, which can detect the goods’ shape and internal temperature and analyze the type of goods through spectra. These characteristics help to determine whether it is a hazardous material. In this research, a photoelectric intelligent sorting robot based on an infrared sensor and a Charge Coupled Device (CCD) sensor is designed. The robot’s hardware system is first developed, and then its important components’ model selection is made. The cargo loading module is designed according to the size of the cargo to be sorted. The cargo information collection module comprises multi-infrared sensors and CCD sensors, and the robot’s hardware is logically connected. In the sorting process, the cargo information is required for model training, the SSD_inception network model is used for training, and the Sort_target data structure is defined to label different cargo information. In the test, the design-based robot, with the increase of measurement distance, the relative distance error of detecting cargo shows an increasing trend, but the error is within 5%. The cargo ID can be determined through the information received by multiple photoelectric level sensors, and they are placed in the designated area, thus successfully achieving the sorting of cargo.

Optimization and verification of mechanical design for small total reflection optics

Mechanical performance assurance is one of the key concerns in the design of small total reflection optics. This article addresses the issue of insufficient strength margin in the design of a total reflection optics for a space photoelectric sensor. Firstly, structural design optimization research was conducted on the optics, and the effectiveness of structural improvement was verified through finite element analysis; Secondly, a concave analysis was conducted under mechanical test conditions to further reduce the risk; Afterwards, the accuracy of the simulation results was verified by comparing the simulation with the experiment through small-scale random vibration tests; Finally, sine vibration tests, random vibration tests, shock tests, acceleration tests were conducted on the entire machine, and optical tests were conducted before and after the tests. The experimental and testing results indicate that the entire machine has passed the mechanical test assessment at the appraisal level and maintained good optical performance. The total reflection optics optimized by mechanical design meets the requirements of engineering applications.

Research on Fire-Detection Algorithm for Airplane Cargo Compartment Based on Typical Characteristic Parameters.

To clarify the reasons for inaccurate fire detection in aircraft cargo holds, this article depicts research from the perspective of a single type of sensor detection. In terms of fire smoke, we select dual-wavelength photoelectric smoke sensors for fire-data collection and a genetic algorithm to optimize the classification and detection of random forest fires. From the perspective of fire CO concentration, we use PSO-LSTM to train a CO concentration compensation model to reduce sensor measurement errors. Research is then conducted from the perspective of various types of sensor detection, using the improved BP-AdaBoost algorithm to train a fire-detection model and achieve the high-precision identification of complex environments and fire situations.

Lightbox: Sensor Attack Detection for Photoelectric Sensors via Spectrum Fingerprinting

Photoelectric sensors are utilized in a range of safety-critical applications, such as medical devices and autonomous vehicles. However, the public exposure of the input channel of a photoelectric sensor makes it vulnerable to malicious inputs. Several studies have suggested possible attacks on photoelectric sensors by injecting malicious signals. While a few defense techniques have been proposed against such attacks, they could be either bypassed or used for limited purposes. In this study, we propose Lightbox, a novel defense system to detect sensor attacks on photoelectric sensors based on signal fingerprinting. Lightbox uses the spectrum of the received light as a feature to distinguish the attacker’s malicious signals from the authentic signal, which is a signal from the sensor’s light source. We evaluated Lightbox against (1) a saturation attacker, (2) a simple spoofing attacker, and (3) a sophisticated attacker who is aware of Lightbox and can combine multiple light sources to mimic the authentic light source. Lightbox achieved the overall accuracy over 99% for the saturation attacker and simple spoofing attacker, and robustness against a sophisticated attacker. We also evaluated Lightbox considering various environments such as transmission medium, background noise, and input waveform. Finally, we demonstrate the practicality of Lightbox with experiments using a single-board computer after further reducing the training time.