Journal of Sensor Technology
ISSN / EISSN : 2161-122X / 2161-1238
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 129
Latest articles in this journal
Journal of Sensor Technology, Volume 12, pp 1-17; https://doi.org/10.4236/jst.2022.121001
Surface plasmon resonance (SPR) sensors have grown in popularity owing to their sensitivity, precision, and capacity for a variety of applications, including detection, monitoring, and sensing, among others. Sensitivity and resolution are two areas where this technology has room for development. A plasmonic biosensor based on an asymmetric slotted PCF structure with extremely high sensitivity has been described and theoretically investigated. This high performance sensor is constructed and completely characterized using finite element method in COMSOL Multiphysics software environment. Sensitivity and resolution are analyzed as performance parameters for the proposed sensor. Numerical simulation exhibits the maximum wavelength-sensitivity of 1100 nm/RIU with 9.09 × 10-6 RIU resolution in the broad measurement range of refractive index from 1.30 to 1.44. A polarization controller can be used to fine-tune this extremely sensitive and wide-ranging refractive index sensor to fulfil a variety of practical needs. This is performed with the consideration of the variation in the refractive index (RI) of the analyte channels. In comparison with earlier PCF-based sensors, the fiber design structure is basic, symmetrical, simple to produce, and cost-effective. Because of the asymmetric air holes and higher sensitivities of the refractive index detector, it is possible to identify biomolecules, biochemicals and other analytes.
Journal of Sensor Technology, Volume 11, pp 39-53; https://doi.org/10.4236/jst.2021.113003
The development of a simple and accurate quantitative method for the determination of 6-mercaptopurine (6-MP) is of great importance because of its serious side effects. Ratiometric fluorescence (RF) sensors are not subject to interference from environmental factors, and exhibit enhanced precision and accuracy. Therefore, a novel RF sensor for the selective detection of 6-MP was developed. The present work reports a sensitive and selective RF sensor for the detection of 6-mercaptopurine, by hybridizing carbon nanodots (CDots) and gold nanoclusters (AuNCs) capped with bovine serum albumin (BSA). The CDots serve as the reference signal and the AuNCs as the reporter. On addition of the 6-MP, AuNCs formed aggregates, because the existing cross-links within the AuNCs and BSA structure were broken in favour of the Au-S bonds, which can enhance the fluorescence of AuNCs, while the fluorescence of CDots is stable against 6-MP, leading to distinct ratiometric fluorescence changes when exposed to 6-MP. 6-MP could be detected in the range of 0 - 30.22 μM with a detection limit of 54 nM. The developed sensor was applied for the determination of 6-MP in human serum samples and satisfactory results were obtained.
Journal of Sensor Technology, Volume 11, pp 1-17; https://doi.org/10.4236/jst.2021.111001
The high tech industrial revolution in the last fifty years depleted and ruined the planet natural resources. Energy harvesting is the main challenge in the research in green technologies. Compact wideband efficient antennas are crucial for energy harvesting portable sensors and systems. Small antennas have low efficiency. The efficiency of 5G, IoT communication and energy harvesting systems may be improved by using wideband efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the small antenna feed line. Ultra-wideband portable harvesting systems are presented in this paper. This paper presents new Ultra-Wideband energy harvesting system and antennas in frequencies ranging from 0.15 GHz to 18 GHz. Three wideband antennas cover the frequency range from 0.15 GHz to 18 GHz. A wideband metamaterial antenna with metallic strips covers the frequency range from 0.15 GHz to 0.42 GHz. The antenna bandwidth is around 75% for VSWR better than 2.3:1. A wideband slot antenna covers the frequency range from 0.4 GHz to 6.4 GHz. A wideband fractal notch antenna covers the frequency range from 6 GHz to 18 GHz. Printed passive and active notch and slot antennas are compact, low cost and have low volume. The active antennas may be employed in energy harvesting portable systems. The antennas and the harvesting system components may be assembled on the same, printed board. The printed notch and slot antennas bandwidth are from 75% to 100% for VSWR better than 3:1. The slot and notch antenna gain is around 3 dBi with efficiency higher than 90%. The antennas electrical parameters were computed in free space and near the human body. There is a good agreement between computed and measured results.
Journal of Sensor Technology, Volume 11, pp 55-63; https://doi.org/10.4236/jst.2021.114004
In this study, a simple Arduino-based experiment was designed to examine the acceleration of the object during free fall and to calculate the value of “g” (acceleration due to gravity). Experimental data on the free fall of a plastic box through the air was gathered with the help of an ultrasonic distance sensor (HC-SR04). Readings were taken at different intervals during the fall to obtain distance time curves. Acceleration during the free fall was then determined by applying the standard kinematic equations. The shape of the distance-time graphs obtained from the experimental setup was in good agreement with the predicted graphs and the calculated values of g lie within the expected range. After repeated experiments, value of gravitational acceleration was found to be 9.805 m/s2. Hardware and software prepared for the experiment are sufficient to examine movement of ordinary objects during free fall, therefore the experiment can be easily settled in a laboratory for the purpose of learning and teaching.
Journal of Sensor Technology, Volume 11, pp 19-38; https://doi.org/10.4236/jst.2021.112002
Sensors are often based on minimalistic microcontrollers for their reduced power consumption and size. Because of the specific hardware of sensors, their software development, including debugging, is also particular. Simulators and external computers are conventional approaches to sensor debugging, but they both face limitations such as the supported hardware and debugging conditions. In this paper, we propose a fully autonomous on-chip debugging solution for sensors (and other devices) based on AVR microcontrollers, with a particular focus on human-machine interaction. The proposal is then validated in practice through various experiments, notably involving real-world sensors. Formal measurement of the induced overhead is also conducted, which eventually demonstrates the applicability of the proposal.
Journal of Sensor Technology, Volume 10, pp 47-59; https://doi.org/10.4236/jst.2020.104004
A robotic wheelchair is assumed to be capable of doing tasks like navigation, obstacle detection, etc. using sensors and intelligence. The initial part of the work was development of a cap controlled wheelchair to test and verify the gesture operation. Following that, a real time operating wheelchair was developed consisting of mode changing option between joystick control mode and head gesture control mode as per as the user’s requirement. The wheelchair consists of MPU6050 sensor, joystick module, RF module, battery, dc motor, toggle switch and Arduino. The movement of the head is detected by MPU6050 and the signal is transmitted to the microcontroller. Then the signal is processed by controller and motion of wheelchair is enabled for navigation. The wheelchair was capable of moving left, right, forward and backward direction. The speed of the wheelchair was 4.8 km/h when tested. Design objective of the wheelchair included cost effectiveness without compromising safety, flexibility and mobility for the users.
Journal of Sensor Technology, Volume 10, pp 1-13; https://doi.org/10.4236/jst.2020.101001
Fiber optic displacement sensors are widely used in industry. Retro reflective fiber optic displacement sensor consists of parallel fibers with a reflector at a distance. Light is launched into the transmitting fiber which gets reflected by reflector. This reflected light is collected by the receiving fiber. The received light is function of the displacement of the reflector from the fiber end faces. This paper is targeted to obtain a robust design for the fiber optic displacement sensor (FODS) using well known Taguchi method. The design takes care of all noise parameters within constraints of manufacturing tolerances. The statistical data analysis is performed on the simulated results. The larger the better signal to noise quality characteristics is used to find the effect of control parameters in the data analysis. Taguchi analysis suggests dominant parameters, which affects the sensitivity of the FODS and causes immunity to noise. A source fiber inclination angle is chosen as an adjustment parameter. Other control parameters are used for fine tuning of the FODS design for achieving three qualities viz. best robustness, optimized sensitivity and robustness and best sensitivity.
Journal of Sensor Technology, Volume 10, pp 15-30; https://doi.org/10.4236/jst.2020.102002
The recent advances in sensing and display technologies have been transforming our living environments drastically. In this paper, a new technique is introduced to accurately reconstruct indoor environments in three-dimensions using a mobile platform. The system incorporates 4 ultrasonic sensors scanner system, an HD web camera as well as an inertial measurement unit (IMU). The whole platform is mountable on mobile facilities, such as a wheelchair. The proposed mapping approach took advantage of the precision of the 3D point clouds produced by the ultrasonic sensors system despite their scarcity to help build a more definite 3D scene. Using a robust iterative algorithm, it combined the structure from motion generated 3D point clouds with the ultrasonic sensors and IMU generated 3D point clouds to derive a much more precise point cloud using the depth measurements from the ultrasonic sensors. Because of their ability to recognize features of objects in the targeted scene, the ultrasonic generated point clouds performed feature extraction on the consecutive point cloud to ensure a perfect alignment. The range measured by ultrasonic sensors contributed to the depth correction of the generated 3D images (the 3D scenes). Experiments revealed that the system generated not only dense but precise 3D maps of the environments. The results showed that the designed 3D modeling platform is able to help in assistive living environment for self-navigation, obstacle alert, and other driving assisting tasks.
Journal of Sensor Technology, Volume 10, pp 31-45; https://doi.org/10.4236/jst.2020.103003
This paper represents the performance analysis of the different shapes of antenna balun and feeding techniques for step constant tapered slot antenna. This work also addresses the benefits of antenna balun (circular and rectangular) along with two types of feeding techniques (Microstrip line L-shape and Microstrip line I-shape). The performance of the antenna for each technique is thoroughly investigated using Computer Simulation Technology (CST) Microwave Studio software simulation under the resonant frequency of 5.9 GHz. Results demonstrate that the proposed model is an effective tool for improving antenna performance. Moreover, an extensive comparison has been carried out between the two different shapes, with and without antenna balun and between two feeding techniques focusing on return losses, gain, directivity, and voltage standing wave ratio (VSWR).
Journal of Sensor Technology, Volume 09, pp 27-34; https://doi.org/10.4236/jst.2019.92003
In this paper, a high sensitive photonic crystal fiber (PCF) based surface plasmon resonance (SPR) biosensor is numerically studied. In this structure, as a plasmonic material, gold (Au) is used because of its chemical activeness. And a layer of sensing medium is used outside of the fiber to make the structure effective. Any unknown biomolecular analyte can be detected by placing or flowing it on the metal surface. Guiding properties and results are investigated using Finite element method (FEM). Results show that maximum sensitivity is 4000 nm/RIU, as well as resolution, is 2.5 × 10−5 RIU of the proposed sensor.