Liquid Crystal Display Research Articles

Green fitness tech: A self-powered device for monitoring treadmill metrics

This research presents the development of a self-powered device designed to monitor treadmill metrics, including speed, distance covered, and calories burned, without requiring external power sources. The purpose of this study is to provide a cost-effective and sustainable alternative to conventional treadmill tracking systems that are often expensive and energy-dependent. The device utilizes an Arduino Nano microcontroller, a DC motor functioning as a generator, an TFT display, and an encoder to sense motor speed and position. Experiments demonstrated the system’s ability to accurately capture and display treadmill data in real-time, powered solely by the kinetic energy generated from treadmill operation. Significant findings highlight the system's capacity to reduce power consumption and operational costs while maintaining performance comparable to more expensive integrated tracking systems. The conclusions drawn from this study suggest that the proposed device not only promotes energy efficiency but also offers a practical, low-cost solution for enhancing the fitness experience, making it an attractive alternative for both personal and commercial treadmill applications.

Arduino-Based Real-Time ECG Monitoring System for Heart Signal Visualization

Electrocardiogram (ECG) monitoring is an essential tool in healthcare for diagnosing and tracking heart conditions. However, existing ECG devices are often expensive, limiting accessibility for personal or educational use. This project aims to develop a low-cost ECG monitoring system using an Arduino UNO, AD8232 sensor, and TFT SPI display. The system collects ECG signals via electrodes and displays the real-time PQRST waveform on the TFT screen and the Arduino IDE serial monitor. Resistors are utilized to ensure signal clarity by reducing electrical noise. The project successfully demonstrated the ability to visualize clear ECG signals in real time, offering a practical and cost-effective solution for continuous cardiac monitoring

Development of an ESP32 Microcontroller-based Colorimeter with an Android App for the Verification of Roasting Degree of Coffee Beans

A lo w-cost and portable colorimeter was developed using an ESP32 microcontroller and a TCS34725 color sensor to monitor the degree of coffee roast, crucial for maintaining flavor consistency and controlling product quality across different batches. The colorimeter detected color recognition resulting in RGB color intensity values, which could be displayed on the device’s TFT LCD touchscreen. Additionally, colorimetric data was transmitted in real-time via WiFi and stored in a MySQL database using an Android app created with the MIT App Inventor platform. The colorimeter was powered by a rechargeable lithium phosphate battery. The consistency of coffee roasting was ensured by self-identifying the standard RGB values of the roasted coffee beans at five degrees (light, light-medium, medium, medium-dark, and dark) with the app. The darker the color of the roasted coffee, the lower the RGB values were gained. The color detection was highly precise, with a relative standard deviation of less than 5%.

VO2·xH2O nanoribbons as high-capacity cathode material for aqueous zinc-ion batteries: Electrolyte selection and performance optimization

In the pursuit of efficient energy storage solutions for renewable energy, aqueous zinc-ion batteries (ZIBs) have emerged as promising contenders, offering high capacity and manufacturability. Among transition metal oxides, vanadium dioxide (VO2) stands out as the synergestic behavior of H+ and Zn2+ ions with the VO2·xH2O ensures high specific capacity in Zn-ion based battery. Here, we present the successful synthesis of hydrated vanadium oxide (VO2·xH2O) nanoribbons via the hydrothermal method, followed by comprehensive characterizations to assess material properties. A systematic study on electrolyte selection, focusing on achieving high capacity and stability, was conducted using varying electrolyte types and concentrations. The superior 3 M Zn(CF3SO3)2 electrolyte was chosen for further electrochemical investigations, leading to the formation of a two-electrode system comprising VO2·xH2O//Zn half-cell ZIB, which lasts more than 1000 cycles at 1 A g−1 in addition to capacity retention of 82.18% while providing a capacity of 235.63 mAh g−1 at 0.1 A g−1, while demonstrating favorable rate capability. Ex-situ XRD analysis unveiled insights into the designed ZIB's charging/discharging mechanism, showcasing variations in cathode crystallinity and the formation of Zn(OH)2 peaks during cycling. To establish the effective usage of this formed ZIB for daily-life applications, the coin cell was effectively used to power an LED and LCD screen, and the subsequently attained value of capacity was compared along with the available literature. This work surpasses existing ZIBs in terms of capacity and cyclability, paving the way for a more sustainable future through efficient energy storage from renewable sources.

Manipulate dynamic chemical interactions in renewable polymers for 3D printing tunable, healable, and recyclable metamaterials

Mechanical metamaterials have garnered significant interests due to their unique properties, which arise from the periodic structures of their constituent units. However, traditional mechanical metamaterials suffer from limitations of fixed properties of the constituent units or irreversibility if they are damaged or little-to-no recyclability. Addressing this challenge, herein, a photoresin consisting of a monomer synthesized from a renewable biomass—epoxidized soybean oil (ESO)—citric acid (CA) and other components was developed for light-based 3D printing. It is discovered that the UV irradiation initiates photopolymerized of the highly photoactive epoxidized soybean oil-ethyl acrylamide (ESO-EA) monomer while enabling the epoxy-acid reaction (EAR) of the epoxy groups in ESO-EA with carboxyl groups in CA to create dynamic chemical bonds (DCBs). This formed dynamic crosslinking network endows the printed material with tunable tensile strengths (0.3–10.4 MPa) and shape memory behaviors (transition temperature: 22–48 °C) while maintaining high stretchability (fractural strain: 81 %–205 %). Thermal annealing facilitates dynamic transesterification reactions (DTER) to further improve the mechanical properties while making the printed materials healable and recyclable. By integrating these innovations into liquid crystal display (LCD) based 3D printing, we demonstrate origami metamaterials with tunable, multi-stable mechanical behaviors as well as property recovery after self-healing of the damaged structures by both simulations and experiments. Finally, the printed metamaterials can be recycled with the well-preserved properties.

Rancang Bangun Water Treatment di Atas Kapal dengan Reverse System Menggunakan Atmega 2560

Ships as an important means of transportation require the availability of good quality fresh water to meet the daily needs of the crew. Because the quality of fresh water that does not meet the standards can interfere with the activities of the crew. This research aims to build a water treatment system on board controlled by ATMEGA 2560 microcontroller. The system is equipped with turbidity sensor SEN0189, TDS sensor SEN0244, and PH sensor SEN0161 to monitor the freshwater quality. The process of working this tool by treating fresh water which then the parameters are detected by the PH sensor, TDS sensor, and turbidity sensor which then the detection results are displayed on the LCD monitor, and the buzzer and LED turn on when the condition of the fresh water parameters does not meet the standards. The methodology and design of this system will be carried out with experimental research methods where in this method at least one variable is manipulated to study the cause-and-effect relationship. The results of testing water treatment using ATMEGA 2560 show that the system can work optimally in treating fresh water. And the accuracy of the PH sensor, TDS sensor, and turbidity sensor is quite accurate with the difference in error with the comparison measuring instrument less than 5%.

Consistency of the Non-Invasive Monitoring Preemie Car Seat (PreeCASE) Device in Assessing Heart Rate, SpO2 Level, and Body Temperature of the Infants

Advancements in technology have made pulse oximeter devices the preferred choice for parents monitoring their baby's health. However, existing devices present challenges for infants, especially preemies, who need continuous monitoring after being discharged from the hospital. Using conventional baby car seats with wired connections and unstable external vital sign monitors may lead to inaccurate data readings. To resolve this issue, the non-invasive monitoring preemie car seat (PreeCASE) device is well-developed. In this study, we focus on investigating the consistency of the PreeCASE device in assessing the heart rate, SpO2 level, and body temperature of healthy infants. For the methods, ten healthy infants are selected to use the PreeCASE device, and the data is collected and analyzed using standard procedure. The PreeCASE device provides consistent data readings for the three main physiological parameters, heart rate SpO2 level, and body temperature that are displayed on an LCD screen based on the user’s respective levels. The PreeCASE device is precisely designed to facilitate easy and rapid monitoring of infants, especially preemie infants. This innovative device holds significant potential to improve and support pediatricians in effectively caring for infants in Malaysia.

Ocular Accommodative and Pupillary Responses During Fixation on Augmented Reality With a Maxwellian Display.

This study aimed to investigate the changes in ocular refraction and pupillary diameter during fixation on augmented reality (AR) images using a Maxwellian display. Twenty-two healthy young volunteers (average age, 20.7 ± 0.5 years) wore a Maxwellian display device in front of their right eye and fixated on an asterisk displayed on both a liquid-crystal display (real target) and a Maxwellian display (AR target) for 29 seconds (real as a baseline for 3 seconds, AR for 13 seconds, and real for 13 seconds) at distances of 5.0, 0.5, 0.33, and 0.2 meters. A binocular open-view autorefractometer was used to measure the ocular refraction and pupillary diameter of the left eye. Accommodative (5.0 meters, 0.28 ± 0.29 diopter [D]; 0.5 meter, -0.12 ± 0.35 D; 0.33 meter, -0.43 ± 0.57 D; 0.2 meter, -1.20 ± 0.82 D) and pupillary (5.0 meters, 0.07 ± 0.22 mm; 0.5 meter, -0.08 ± 0.17 mm; 0.33 meter, -0.16 ± 0.20 mm; 0.2 meter, -0.25 ± 0.24 mm) responses were negative when the real target distances were farther away. The accommodative response was significantly and positively correlated with the pupillary response during fixation on the AR target (R2 = 0.187, P < 0.001). Fixating on AR images using a Maxwellian display induces accommodative and pupillary responses. Accommodative responses depend on the distance between real objects. Overall, the Maxwellian display does not completely eliminate accommodation in real space.

Optimization of stimulus properties for SSVEP-based BMI system with a heads-up display to control in-vehicle features.

Over the years, the driver-vehicle interface has been improved, but interacting with in-vehicle features can still increase distraction and affect road safety. This study aims to introduce brain-machine interface (BMI)- based solution to potentially enhance road safety. To achieve this goal, we evaluated visual stimuli properties (SPs) for a steady state visually evoked potentials (SSVEP)-based BMI system. We used a heads-up display (HUD) as the primary screen to present icons for controlling in-vehicle functions such as music, temperature, settings, and navigation. We investigated the effect of various SPs on SSVEP detection performance including the duty cycle and signal-to-noise ratio of visual stimuli, the size, color, and frequency of the icons, and array configuration and location. The experiments were conducted with 10 volunteers and the signals were analyzed using the canonical correlation analysis (CCA), filter bank CCA (FBCCA), and power spectral density analysis (PSDA). Our experimental results suggest that stimuli with a green color, a duty cycle of 50%, presented at a central location, with a size of 36 cm2 elicit a significantly stronger SSVEP response and enhanced SSVEP detection time. We also observed that lower SNR stimuli significantly affect SSVEP detection performance. There was no statistically significant difference observed in SSVEP response between the use of an LCD monitor and a HUD.

Mechanical behavior of dumbbell-type metamaterials constructed with elliptic curves

In this paper, based on the traditional concave ortho-hexagonal honeycomb (CHH), its curvilinear modified design was introduced into the elliptic curve configuration, and a novel dumbbell-shaped honeycomb (DH) was proposed. All specimens were prepared by Liquid Crystal Display (LCD) light-cured 3D printing. The aim of this study is to investigate the deformation and damage behavior and mechanical properties of DH and CHH under in-plane quasi-static uniaxial compression and tension. The effects of variation of the cell parameters semi-major axis length a and semi-minor axis length b on the deformation, damage behavior and mechanical properties of DH have been investigated. The experimental results show that the DH incorporating the elliptical curvilinear design has a reduced internal compressive strength under compression, but the negative Poisson’s ratio property is enhanced, which is 17% higher compared to the CHH, and the tensile strength under tension is reduced compared to the CHH, but the tensile ultimate strain is increased by 25% compared to the CHH. This will help to improve the problem of stress concentration and negative Poisson’s ratio in the process of deformation of conventional structures. Differences in the a and b parameters in the DH structure will have different effects on its deformation-fracture behavior and mechanical properties.

Realization of narrow-band blue emission based on structurally engineering-designed Bi3+-doped phosphors

The exploration of efficient narrowband emission phosphors is crucial for white light-emitting diodes (WLEDs) in high-performance backlighting applications. Up to now, the discovery of narrow-band Bi3+-doped phosphors for emerging applications remains challenging because Bi3+ typically exhibits broadband emission properties. A novel narrow-band blue phosphor (Ca4SnGe3O12:Bi3+) was successfully synthesized, benefiting from the highly symmetric crystal environment and tightly connected rigid structure of the garnet structure. The phosphor demonstrates broad excitation in the near-ultraviolet (n-UV) region and emits narrowband blue light at 442 nm (FWHM = 36 nm) with a color purity of 94.7 %. In this paper, the assignment of different luminescence centers and the use of Zr/Hf to partially replace Sn to enhance luminescence performance are studied. The reasons for the consequent changes in luminescence behavior are explained in detail. The use of narrowband commercial red K2SiF6:Mn4+, green β-Sialon:Eu2+, and synthetic blue luminescent materials as RGB emitters covered 81 % of the National Television System Committee (NTSC) color space, demonstrating great potential for liquid-crystal-display (LCD) backlight use.

Ultra high-speed 3D shape measurement technology for specular surfaces based on μPMD

Phase measuring deflectometry (PMD) has been extensively applied to measure specular surfaces due to its non-contact, high-precision, full-field measurement capabilities. Liquid crystal display (LCD) screen is the most common structured light source in PMD. However, the response time of liquid crystal molecules limits its frame rate to around 100 frames per second (fps). Therefore, it is quite difficult for traditional PMD to measure rapidly moving surfaces. This paper proposes a 3D dynamic sensing technique, microsecond-PMD (µPMD) based on the high-frame-rate sinusoidal fringe display (HSFD). In the proposed method, the switching time for each fringe pattern display is at a sub-microsecond level, enabling high-speed fringe acquisition with kHz-level area array detection or 100kHz-level line array scanning. The HSFD method uses a specially designed LED array and two-step optical expansion. The high-speed switching characteristic of LED sources is utilized to allow a superfast display rate. Moreover, the superior sinusoidal property can be achieved by the combination of the specially designed discrete sinusoidal LED array, the light-diffracting effect of orthogonal gratings, and the filtering effect of the light diffuser. The mechanism and analytic model of fringe generation are thoroughly analyzed and discussed in this work. Furthermore, the swarm optimization algorithm and corresponding weighted fringe quality evaluation function are presented to obtain the optimal fringes. To the best of our knowledge, the proposed µPMD, for the first time, achieved a superfast fringe acquisition rate of 4000fps with sub-micrometer precision in three-dimensional (3D) reconstruction for specular surfaces. We envision this proposal to be broadly implemented for real-time monitoring in manufacturing.

Dimension compensation of printed master molds by a desktop LCD 3D printer for high-precision microfluidic applications.

Recent advances in low-cost liquid crystal display (LCD) 3D printing have popularized its use in creating microfluidic master molds and complete devices. However, the quality and precision of these fabrications often fall short of the rigorous standards required for advanced microfluidic applications. This study introduces a novel approach to enhance the dimensional accuracy of microchannels produced using a desktop LCD 3D printer. We propose a method for dimension compensation, optimize the printing parameters, and provide a straightforward post-treatment technique to ensure high-quality curing of polydimethylsiloxane (PDMS) in master molds made from photosensitive resin. Our investigation assesses the precision of 3D printing across three different scales of square cross-section microchannels by measuring their widths and heights, leading to the determination of optimal printing parameters that minimize dimensional errors. The dimensional errors are further reduced by introducing a series of dimension compensation factors, which correct the nominal dimensions of the microchannels by using the compensation factors in 3D printing. The dimensional accuracy is significantly improved after compensation even in fabricating complex microchannels of triangular cross-sections. Finally, a spiral channel of trapezoidal-like cross-section with tilted edges is fabricated for microfluidic application, and highly efficient particle separation is realized in the channel. The proposed method provides new insights for utilizing desktop LCD 3D printers to achieve high-accuracy microstructures necessary for advanced microfluidic applications.

Development of a Frugal Onboard Tire Pressure Monitoring Control System

Tires, the bridge between vehicles and roads, play an unparalleled role in both performance and safety. In everyday use, the tire health is often neglected, with factors such as tread depth, inflation pressure, and tire damage overlooked by most users, leading to ∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document}30% of cars in developed nations, operating with underinflated tires, a situation exacerbated in developing nations. Hence, innovations such as tire Pressure Monitoring Systems have become imperative. The objective of the current work is to develop an economical, direct, on-board tire pressure monitor for automotive tire health upkeep. This is achieved through the integration of a pressure sensor and transmitter with an Arduino, and wireless transmission of the data to the dashboard display. While the initial model, tested on a bicycle, effectively displayed tire pressure on the handlebar-mounted LCD screen with an accompanying LED indicating deviations from the standard pressure, the current design has lot of scope for improvement by the utilization of a wireless technologies for the pressure sensors for continuous monitoring of tire pressures in a range of vehicles from two-wheelers to heavy vehicles.

Design of wireless charging system for E-Vehicle

To address the dual problems of fuel reliance and air pollution, this study describes the design of a wireless ground to vehicle charging system powered by solar energy and specifically designed for electric vehicle (EV) charging stations. As the number of electric vehicles on the road steadily rises, they present a viable way to cut travel expenses by switching from conventional fuel to electricity, which is a more economical and sustainable option. With the introduction of a wireless EV charging system, this creative solution does away with the need for external power sources and permits continuous charging without interfering with driving. Utilizing solar power, the charging system incorporates solar panels, batteries, circuit regulators, boost converters, receiver and transmitter copper coils, AC/DC converters, microcontrollers (such as ATmega), LCD screens, and circuit regulators. This study describes a technique that shows that charging electric cars while driving is feasible and eliminates the need to stop. This technology for wireless solar electric vehicle charging presents a forward-thinking approach to sustainable mobility by providing a workable solution that can be easily included in the road infrastructure. For the wireless charging, in addition, various coil designs are suggested.

Implementation of Solar Panels as an Alternative to Electric Power Used in WiFi-based Freezer Box Temperature Monitoring System (Case Study of NN Frozen Food Wajak)

A freezer box temperature monitoring system using solar panels as alternative power is an important technology to ensure the quality of stored products. This research develops a WiFi-based temperature monitoring system that uses a DS18B20 temperature sensor, a PZEM-004T digital sensor, and an ESP8266 module to read and send real-time data to a website platform. Data is collected through a temperature sensor connected to the ESP8266 microcontroller, then displayed on the LCD screen and uploaded to the server for further monitoring via WiFi connection. The results show that this system successfully maintains the freezer box temperature at optimal conditions with an average temperature value of -24.82°C and a temperature range ranging from -28.81°C to -19.63°C. The voltage values are in the range of 197.10 V - 218.70 V, current between 0.02 A - 1.03 A, and power between 158 W - 186.80 W.

Effects of Glass Transmittance, Font Brightness and Font Size on Text Legibility in LCD Home Appliance Interface

This study experimentally investigated the impacts of major design variables of a liquid crystal display (LCD) home appliance control interface on interface text legibility. The home appliance of interest was a washing machine. The experimental setup simulated a real-world washing machine usage condition challenging in terms of visual information processing. Independent variables were surface glass transmittance (25%, 50%, and 75%), font brightness (60%, 75%, and 100% at 25, 44, and 90 cd/m²), and font height (3, 5, and 7 mm). Response time (RT) and proportion of errors (PE) were employed as the dependent measures. Regression analysis was conducted to analyze data. The results showed that: (a) an increase in the font height resulted in decreases in RT and PE, and (b) increasing glass transmittance and font brightness reduced RT and PE for the 3 and 5 mm font heights. The study findings would inform the design of home appliance control interfaces.

Machine-learning-based sampling inspection under OQC capacity for real-time quality monitoring in the TFT-LCD industry

ABSTRACT In the thin film transistor-liquid crystal display (TFT-LCD) industry, the competition is fierce, and the external failure cost is high. To improve the quality of released products, sampling inspection under outgoing quality control (OQC) is conducted before products are released. Owing to the variety and complexity of inspection items, the task must be carried out manually while realising automation is difficult. Traditional random sampling inspection is limited by sampling quantity, manpower, and material resources. To effectively improve acceptable quality levels, this paper proposes a quality predictive monitoring framework tailored to the production and inspection characteristics of the TFT-LCD industry. This framework includes real-time automatic quality monitoring based on an optimal machine learning prediction model with two-phase feature creation, and it also addresses OQC inspection capacity constraints. Experimental results show the prediction performance based on proposed model is better than the traditional random sampling process. In practice, superior average outgoing quality improves by more than 70% at the same sampling level. In addition, the features of the process can be further controlled and managed based on the prediction model to monitor the key parameters in real time and respond to abnormalities quickly, thereby further improving the quality of released products.

Transition metal-catalyzed C(sp2/sp3)-H α-fluoroalkenylation from gem-(bromo/di)fluoroalkenes to monofluoroalkenes: scope, mechanisms, and synthetic applications.

Organofluorines have a broad range of industrial applications, such as pharmaceuticals, liquid crystal displays (LCDs), solar cells, textiles, and construction coatings, and are used in peptidomimetics, surfactants, refrigerants, anesthetics, and agrochemicals. Among them are versatile monofluoroalkenes that play a crucial role in medicinal and synthetic chemistry. The synthetic strategies for this class of molecules are limited, and prior efforts frequently suffered from poor atom- and step-economies. As a surrogate pathway for traditional cross-coupling transformations, transition metal (TM)-catalyzed C-H direct α-fluoroalkenylation overcomes these obstacles and provides straightforward techniques to access monofluoroalkenes. Nevertheless, substrate scope is still a challenge for catalysis, where gem-bromofluoroalkene synthons are applicable with electronically biased substrates such as azoles, while gem-difluoroalkene-based strategies are limited to substrates containing N-based directing groups. Herein, we review the cutting-edge fluoroalkenylation research for direct synthesis of monofluoroalkenes achieved during the last decade (2013-2023). This review is divided into two main parts: the first part discusses TM-catalyzed direct α-fluoroalkenylation via the merging of C-H activation and C(sp2)-Br cleavage strategies using gem-bromofluoroalkenes, and the second part describes the same reaction, albeit with C(sp2)-F cleavage of highly explored gem-difluoroolefins. Our review surveys all previously reported monofluoroalkenes in this research area, including their preparation techniques, stereoselectivity, and yield percentages. Furthermore, optimal conditions, reactant scope, mechanistic investigations, synthetic applications, benefits, and drawbacks of each presented methodology are critically discussed.

Base-Mediated Chemodivergent [4 + 1] and [2 + 1] Cycloadditions of N-Alkylpyridiniums and Enones.

Divergent synthesis of structurally different products from the same kinds of starting materials is highly synthetically useful but very challenging. Herein, we reported a base-mediated chemodivergent [4 + 1] and [2 + 1] cycloaddition of N-alkylpyridinium and enone under mild conditions, leading to furan-fused bicycles with high diastereoselectivity and spirobicycles, respectively, from moderate to high yields. N-Alkylpyridinium salts were modular nucleophilic transfer reagents and C1 synthons, which underwent tandem Michael addition to the α,β-unsaturated ketones and cyclization under the base conditions. Late-stage derivatization of 4-propyldicyclohexylanone from an important industrial raw of liquid crystal display (LCD) screens was realized. In vitro, compound 3f exhibited good activities against human colon cancer cells (HCT116) with IC50 values in 9.82 ± 0.27 μM. Further biological evaluations investigated the mechanism of the effective inhibition of cell growth, including apoptosis ratio detection, cell cycle analysis, and migration capacity of HCT116 cells. In apoptosis effect studies, complex 3f increased the percentage of apoptotic HCT116 cells to 26.8% (15 μM).