PDMS Film Research Articles

Biomimetic hair-assisted GaN optical devices for bidirectional airflow detection

Airflow sensing plays a pivotal role in numerous fields, including medicine, industry, and environmental monitoring. However, detecting bidirectional airflow using a single sensing unit poses significant challenges. In this work, a miniature airflow sensing device is introduced, utilizing a GaN optical chip integrated with a biomimetic hair structure. The sensing device comprises a monolithic GaN chip that handles both light emission and detection. The biomimetic hairs, constructed from nylon fibers and PDMS film, undergo structural bending in converting airflow signals into optical changes, modulating the light captured by the on-chip detector. The intensity of the airflow directly correlates with the bending extent of the biomimetic hair, facilitating the precise detection of airflow rates through changes in the photocurrent. The integrated device can measure a wide range of airflow rates from −23.87 ms−1 to 21.29 ms−1, and exhibit a rapid response time of 13 ms and a detection limit of 0.1 ms−1. Characterized by its compact size, fast response time, and bidirectional detection ability, the developed device holds immense potential for applications in breath detection, speech recognition, encoding information, and the realization of logic operations.

High-Performance Triboelectric Nanogenerator Based on Silk Fibroin-MXene Composite Film for Diagnosing Insomnia Symptoms.

In this study, we developed a flexible, biocompatible, and high-output electrical performance triboelectric nanogenerator (TENG) employing a silk fibroin (SF)-MXene composite film (SF-MXene-F) and a PDMS film as the friction layer. The inclusion of MXene in the SF film increased its surface charge density, presenting a practical approach to designing high-performance SF composite film-based TENGs. At a MXene content of 40%, our SF-MXene composite film-based TENG (SF-MXene-FTENG) achieved optimal output electrical performance, featuring a maximum open-circuit voltage (Voc) of 418 V, a maximum short-circuit current (Isc) of 11.6 μA, and a maximum output power density of 9.92 W/m2. The Voc and power densities of the SF-MXene-FTENG surpassed previously reported optimal values for SF-based TENGs by 1.6 and 3.8 times, respectively. Furthermore, leveraging the exceptional biocompatibility and light shading performance of TENGs, we designed a wearable smart TENG eye mask capable of diagnosing insomnia symptoms and monitoring sleep quality in real time. The SF-MXene-FTENG holds promising application potential as a wearable electronic device for diagnosing sleep-related diseases.

Rapid-response, low-detection-limit, positive-negative air pressure sensing: GaN chips integrated with hydrophobic PDMS films

Despite the importance of positive and negative pressure sensing in numerous domains, the availability of a single sensing unit adept at handling this dual task remains highly limited. This study introduces a compact optical device capable of swiftly and precisely detecting positive and negative pressures ranging from −35 kPa to 35 kPa. The GaN chip, which serves as a core component of the device, is monolithically integrated with light-emitting and light-detecting elements. By combining a deformable PDMS film coated with a hydrophobic layer, the chip can respond to changes in optical reflectance induced by pressure fluctuations. The integrated sensing device has low detection limits of 4.3 Pa and −7.8 Pa and fast response times of 0.14 s and 0.22 s for positive and negative pressure variations, respectively. The device also demonstrates adaptability in capturing distinct human breathing patterns. The proposed device, characterized by its compactness, responsiveness, and ease of operation, holds promise for a variety of pressure-sensing applications.

In-situ cryogenic X-ray diffraction analysis of Poly(dimethylsiloxane) oil and film

Understanding the phase transitions and crystallographic characteristics of polysiloxane materials poses a significant challenge. To address this issue, a custom cryogenic chamber has been developed and integrated with a laboratory X-ray diffraction apparatus, enabling the execution of in-situ temperature-dependent X-ray diffraction (XRD) analyses across the cooling and heating cycles. Through the utilization of diverse sample holders, the real-time monitoring of crystallization and melting phenomena in both linear poly(dimethylsiloxane) (PDMS) oil and crosslinked PDMS film has been made feasible. Notably, high-quality X-ray diffraction data, encompassing 13 diffraction lines, are successfully acquired for the first time for linear PDMS oil at 153K. Subsequent crystallographic examination has revealed a tetragonal unit cell characterized by lattice parameters a = b = 8.3379 Å, c = 11.9284 Å, and space group I 41, suggesting the adoption of a fourfold helical conformation by two polymer chains, each comprising four monomer units, within the lattice structure. This improved and versatile X-ray instrumentation presents clear advantages over conventional commercial powder X-ray diffractometers, which is anticipated to provide a promising in-situ characterization approach for investigating the low-temperature behaviors of liquid or oil materials.

Crack-Based Composite Flexible Sensor with Superhydrophobicity to Detect Strain and Vibration.

Vibration sensors are widely applied in the detection of faults and analysis of operational states in engineering machinery and equipment. However, commercial vibration sensors with a feature of high hardness hinder their usage in some practical applications where the measured objects have irregular surfaces that are difficult to install. Moreover, as the operating environments of machinery become increasingly complex, there is a growing demand for sensors capable of working in wet and humid conditions. Here, we present a flexible, superhydrophobic vibration sensor with parallel microcracks. The sensor is fabricated using a femtosecond laser direct writing ablation strategy to create the parallel cracks on a PDMS film, followed by spray-coating with a conductive ink composed of MWCNTs, CB, and PDMS. The results demonstrate that the developed flexible sensor exhibits a high-frequency response of up to 2000 Hz, a high acceleration response of up to 100 m/s2, a water contact angle as high as 159.61°, and a linearity of 0.9812 between the voltage signal and acceleration. The results indicate that the sensor can be employed for underwater vibration, sound recognition, and vibration monitoring in fields such as shield cutters, holding significant potential for mechanical equipment vibration monitoring and speech-based human-machine interaction.

Carbonized derivatives derived from the complex of Fe/Ni bimetallic MOFs and phenolic resin for flexible piezoresistive sensors in motion capture and health monitoring

Based on the substantial high surface area and the chemical robustness inherent to metal–organic frameworks (MOFs), their integration into piezoresistive flexible pressure sensors presents significant potential. Nonetheless, the application of such sensors is impeded by the low conductivity of MOFs. In this work, we increased the conductivity of MOFs by carbonizing 2-aminoterephthalic acid iron-nickel metal–organic frameworks (Fe/Ni-MOFs) and introducing phenolic resins to protect the structure of Fe/Ni-MOFs. Piezoresistive flexible sensors were developed by embedding this carbonized derivative on the surface of PDMS films. The senrors showed a sensitivity of 198.51 kPa−1, broad operating pressure range (0–5 kPa), a fast response time (46 ms), a short recovery time (28 ms), and a high abrasion resistance. The flexible pressure device could be applied to monitor the finger motion and human pulses. Overall, these flexible high sensitivity devices demonstrate potential in the fields of wearable technologies, real-time health monitoring, and biomedical applications.

Novel flexible magnetoelastic biosensor based on PDMS/FeSiB/QD composite film for the detection of African swine fever virus P72 protein.

African swine fever (ASF) is a highly contagious and severe hemorrhagic disease caused by the African swine fever virus (ASFV). The continuous spread of ASFV affects the safety of the global meat supply; therefore, the establishment of sensitive and specific detection methods for ASFV has become an important hot spot in food safety. Herein, we developed a flexible magnetoelastic (ME) biosensor based on PDMS/FeSiB/QDs composite films for the detection of ASFV P72 protein. Based on the high luminescence performance of CsPbBr3 quantum dots and the excellent magnetoelastic effect of FeSiB, flexible ME biosensors convert stress signals generated by antibody-antigen-specific binding into optical and electromagnetic signals. The nanostructures covalently linked by quantum dots and PDMS provide biomodification sites for ASFV P72 antibodies, simplifying the functionalization modification process compared to the case of conventional biosensors. The deformation of the PDMS film is amplified, and the conversion of surface stress signals to electrical signals is enhanced by exposing the biosensor to a uniform magnetic field. The experimental results proved that the flexible ME biosensor has a wide linear range of 10 ng mL-1-100 μg mL-1, and the detection limit is as low as 0.079 ng mL-1. Moreover, the flexible ME biosensor also shows good stability, sensitivity and specificity, confirming the potential for early disease screening.

A handheld, wide-range pressure pump for portable microfluidic applications

Pumping is an indispensable operation in microfluidic applications. Numerous simple pumps have been developed to improve the portability of microfluidic systems, but they generally have poor controllability, short duration working time, and narrow pressure range, which compromises the functionality of portable microdevices. To address these limitations, we present a novel handheld, wide-range pressure pump that utilizes a disposable mini gas cylinder as a pressure source and a porous PDMS film as a flow-rate regulator. Specifically, by incorporating a set of parallel porous PDMS films with varying porosity, sectional area, and thickness into the pump system, and selectively switching between the branch flow circuits containing these porous PDMS films, we are able to finely regulate the flow rate of air released from the mini gas cylinder. This capability enables precise control of the pumping pressure applied to microfluidic devices over a wide range, thereby governing the fluid flow rate to accommodate different applications. The compact and lightweight nature of our pressure source renders this pump system particularly advantageous for field-portable microfluidic applications. Additionally, we demonstrate its capabilities through the performance of well-established microfluidic experiments, including concentration gradient generation and emulsion droplet production. We firmly believe that the compactness, operational simplicity, and disposability of our pump will greatly facilitate the widespread adoption of microfluidic technologies, particularly in point-of-care diagnostics and resource-limited settings.

Tb3+‐Doped Ca3Ga4O9 Phosphors with Color‐Tunable Photoluminescence and Non‐Pre‐Irradiation Mechanoluminescence for Multimodal Applications

AbstractMaterials that can emit light under optical/mechanical stimulation are usually called photoluminescent/mechanoluminescent (PL/ML) materials. PL materials are used in diverse fields for half a century. While, ML materials have burst out in the last two decades, and now are showing great application potential in the fields of anti‐counterfeiting, information storage, and stress imaging. It is of great significance to explore new luminescent materials with PL and ML dual response. In this study, Tb3+‐doped Ca3Ga4O9 phosphors with color‐tunable PL and non‐pre‐irradiation ML properties are reported. Ca3Ga4O9 exhibits a broadband blue emission centering at 425 nm, which originates from the 4T2‐4A2 transition of electrons in d orbits of Ga3+. Due to the energy transfer from host to Tb3+, color‐tunable emission from blue to cyan, and ultimately to green can be realized by increasing the concentration of Tb3+. Particularly, ML is seen from Ca3Ga4O9:Tb3+ under grinding and from the Ca3Ga4O9:Tb3+/PDMS film under bending or stretching originated from the triboelectric mechanism. The non‐pre‐irradiation ML behavior is evidenced by the contrast thermoluminescence (TL) experiments. This study not only provides a new candidate toward multi‐purpose luminescent applications, but also demonstrates a good case in which the triboelectric effect can efficiently trigger the non‐pre‐irradiation ML behavior.

Curvature-Insensitive Transparent Surface-Enhanced Raman Scattering Substrate Based on Large-Area Ag Nanoparticle-Coated Wrinkled Polystyrene/Polydimethylsiloxane Film for Reliable In Situ Detection.

Flexible and transparent surface-enhanced Raman scattering (SERS) substrates have attracted considerable attention for their ability to enable the direct in situ detection of analytes on curved surfaces. However, the curvature of an object can impact the signal enhancement of SERS during the measurement process. Herein, we propose a simple approach for fabricating a curvature-insensitive transparent SERS substrate by depositing silver nanoparticles (Ag NPs) onto a large-area wrinkled polystyrene/polydimethylsiloxane (Ag NP@W-PS/PDMS) bilayer film. Using rhodamine 6G (R6G) as a probe molecule, the optimized Ag NP@W-PS/PDMS film demonstrates a high analytical enhancement factor (AEF) of 4.83 × 105, excellent uniformity (RSD = 7.85%) and reproducibility (RSD = 3.09%), as well as superior mechanical flexibility. Additionally, in situ measurements of malachite green (MG) on objects with diverse curvatures, including fish, apple, and blueberry, are conducted using a portable Raman system, revealing a consistent SERS enhancement. Furthermore, a robust linear relationship (R2 ≥ 0.990) between Raman intensity and the logarithmic concentration of MG detected from these objects is achieved. These results demonstrate the tremendous potential of the developed curvature-insensitive SERS substrate as a point-of-care testing (POCT) platform for identifying analytes on irregular objects.

Laser Parallel Nanofabrication of Dual‐Au‐Nanoholes on Microsphere‐Lens‐Array for Polarization‐Dependent SERS

AbstractHigh‐efficient fabrication of well‐ordered nanostructures on flexible substrates is a challenge to surface‐enhanced Raman spectroscopy (SERS) for analytical fingerprinting trace‐detection. In this work, a laser parallel nanofabrication method is reported via incident‐angle‐dependent photonic nanojet ablating Au film on the bottom surface of microsphere‐lens‐array (MLA), for combination with formed dual Au‐nanoholes (MLA/2‐AuNHs) as the flexible SERS substrates. The process parameters, i.e., pulsed laser energy, MLA diameter, Au film thickness, and laser incident angle, are optimized for high finish‐quality of dual‐AuNHs with a diameter of ≈875 nm and a tip gap of ≈90 nm. The SERS substrate demonstrates the limit of detection down to 10−11 M for 4‐nitrobenzenethiol molecules by the multiple optical regulations, including self‐aligned focusing to the hotspots and directional antenna, the strongly localized surface plasmon resonances, and optical whispering‐gallery modes for resonance energy transfer. The flexible PDMS film supporting the rigid MLA holds the SERS performance of MLA/2‐AuNHs with high flexibility. Moreover, the MLA/2‐AuNHs SERS substrate exhibits differential responses to orthogonally polarized excitation, by which the background noises can be eliminated to improve the Raman spectrum. The present work opens new opportunities to fabricate dielectric‐metal flexible SERS substrates by laser parallel nanofabrication via MLA for Raman trace detection.

Dy3+,Mn4+ co-doped phosphors for synergistic luminescent dual-mode thermometer and high-resolution imaging

Fluorescent temperature measurement has become a research hotspot due to its characteristics of non-contact, miniaturization, and fast response. However, it remains a key challenge to realize excellent sensitivity and high resolution. Herein, a series of La2MgTiO6:Dy3+,Mn4+ phosphors are developed and the related energy transfer between Dy3+→Mn4+ is discovered. The coupling distance between Mn4+ and adjacent ligands is greatly affected by temperature. However, the energy differences between the emission energy levels and lower energy levels of Dy3+ hinder the multi-phonon relaxation process, which moderates the thermal quenching rate of Dy3+. Therefore, highly sensitive FIR thermometers are built according to the significant discrimination temperature dependence of Dy3+ and Mn4+. The maximum Sa and Sr reach 0.022 K−1(@563 K) and 2.622 %K−1(@544 K). In contrast, a thermometer based on the emission lifetime of Mn4+ is fabricated, which is extremely sensitive to temperature. Interestingly, Dy3+ can effectively promote the quenching of Mn4+, and then improve the sensitivity. The maximum Sr enhances from 1.621 %K−1(@503 K) to 2.305 %K−1 (@480 K). The high sensitivity and resolution of the dual-mode fluorescence thermometry have exceeded most of the current optical thermal measurement materials. Besides, the thermochromic properties presented by the designed phosphors can be combined with PDMS films to qualitatively evaluate the ambient temperature.

Flexible and twistable free-standing PDMS-magnetic-nanoparticle-based soft magnetic films with robust magnetic properties

In this paper, we develop multifunctional, physically soft, mechanically compliant, and magnetically responsive PDMS films, with embedded Fe3O4 nanoparticles, that show robust magnetic properties over a significant range of mechanical deformation. First, we establish that the magnetic properties, namely the saturation magnetization (M s), remanent magnetization (M r), and intrinsic coercivity (H ci) of these PDMS films in highly deformed configurations, i.e. in folded, twisted (with different twist angles), and bent (flexed) configurations, show very little degradation compared to those obtained in undeformed configurations. Next, the films were subjected to repetitive cycles of zero-to-max deformation (R = 0) and the saturation magnetization of the films was shown to not exhibit any significant degree of progressive degradation as a function of cyclic deformation history. These findings confirm the excellent robustness and cyclic durability of magnetic properties shown by these magnetic and compliant PDMS films and point to their suitability for wearable electronics applications.

A strategy for accelerating condensation by radiative cooling with hydrophilic-hydrophobic surface

Using radiative cooling technology for dew collection is a promising solution to the freshwater resource crisis. Environmental factors such as solar radiation intensity, ambient temperature, and humidity can influence both the radiative cooling process and the condensation process. In this study, the influence mechanisms of environmental factors on the radiation condensation effect are studied through simulation. Then, TiO2 nanoparticles are sprayed on the surface of the PDMS film to form a hydrophobic-hydrophilic surface. The experimental research is conducted at an ambient temperature of 25 ℃ and a relative humidity of 70%−90% to analyze the change in condensation water. The experimental results indicate that after TiO2 nanoparticles are added to PDMS film, the emissivity in the atmospheric transparency window and the surface hydrophilicity of the film are increased, which effectively improves the condensation effect. The condensation rate has reached 916.6 g∙m−2∙h−1. At 70% relative humidity, the condensation water of PDMS film with TiO2 nanoparticles increased by 58%, and the improvement effect is most significant at lower relative humidity. It has great application prospects in arid and water-scarce areas.

Reproducible PDMS flexible superhydrophobic films: A method utilizing picosecond laser-etched templates

This paper provides a convenient, efficient and repeatable method for the preparation of flexible PDMS superhydrophobic films. The stainless steel template was etched with picosecond laser to create textures, which was then filled with PDMS and thermally cured to produce PDMS superhydrophobic films featuring corresponding microstructures. By constructing computational models of the microstructures and exploring the influence of laser scanning spacing on contact angle, the process parameters were optimized to obtain superhydrophobic PDMS films while ensuring the stability of microstructures. The microstructures showed straight lines spaced 55 μm apart, with each line connected by regular truncated cone structures. These structures formed Cassie contacts with the droplets, exhibiting a contact angle of 152.1° and a sliding angle of 9°. In addition, this study demonstrates the reproducibility of the PDMS superhydrophobic film preparation method and its effectiveness in delaying icing. The results indicate that the templates can be used for more than twenty replications, and the obtained PDMS superhydrophobic films have a delayed icing time of 3.3 times. These findings suggest that the PDMS superhydrophobic films have excellent performance and repeatable characteristics, making them suitable for various applications.

High-sensitivity tapered fiber relative humidity sensor based on PDMS and GO films

A new tapered fiber relative humidity (RH) sensor based on polydimethylsiloxane (PDMS) and graphene oxide (GO) film coatings is proposed and demonstrated. Tapered fiber is fabricated in single mode fiber by the tapering machine. The PDMS film is coated on the surface of the fiber using the hydroxide flame sintering technique, while the GO film is deposited using the physical deposition technique. This structure can achieve strong interference effect by the smaller range of tapering process. In the RH measurement experiment, the humidity sensitivity of the sensor is measured to be as high as 0.371 dB/%RH within the RH range of 35% to 90%. The experiment investigates the impact of different numbers of PDMS coating on sensitivity. As the number of PDMS coatings increases, the RH sensitivity of the sensor also increases and reaches the highest sensitivity when coated with 10 layers of PDMS film. The sensor has high sensitivity to RH, good stability and mechanical strength, which also shows great performance in both moisture absorption and desorption. These advantages make the sensor suitable for the wide range of humidity sensing applications.

Pre-bent U-shaped optical microfiber embedded in multilayer PDMS film for large-scale bending measurement

We propose a sensing film for large-scale bending measurements. Bi-conical microfiber was prepared using standard single-mode fiber and placed into pre-bent U-shape embedded with multilayer PDMS (polydimethylsiloxane) film, in which the effect of different ratios on the properties of PDMS was exploited. The shape of the microfiber placed and the structure of multilayer PDMS make the sensing film more responsive to bending, allowing for a wide range of bending angle measurements. And the ability to withstand a large degree of bending and stretching simultaneously enables the application of real-time monitoring and identification of knuckles and other joints. By analyzing the relationship between the output voltage and the bending angle, it successfully distinguished finger movements at different bending angles. In addition, the repeatability and stability of the sensing film were also proved to be excellent. It can be applied in many related fields such as human–computer interaction control, human health monitoring, clinical diagnosis of movement disorders and rehabilitation training.

Enhanced performance triboelectric nanogenerator based on mullite/PVA composites for self-driven sensing and smart home control

Polyvinyl alcohol (PVA) has good biocompatibility, a simple fabrication process, and environmental protection, which is very suitable for the production of triboelectric nanogenerator (TENG) applied to smart home control. However, the output performance of the TENG composed of PVA and PDMS films is not high. Previous research has explored the enhancement of PVA-based TENG performance by doping with conductive materials to modify the dielectric properties of PVA composite films. Nevertheless, this approach is associated with issues of high production costs and energy consumption. This work prepared a mullite/PVA composite material TENG (MP-TENG), the introduction of mullite induced interfacial polarization in the composite film. This effect resulted in the appearance of polarization centers, thereby enhancing the charge-sensing capability of the composite film. Consequently, the triboelectric output performance of the MP-TENG was improved. MP-TENGs with different amounts of mullite fiber doping were prepared, and the maximum output performance was obtained when the doping level reached 3 wt%. At this concentration, the composite film exhibited an open-circuit voltage of 70.89 V and a short-circuit current of 2.45 μA. An enhancement of 1.78 and 1.71 times was achieved with respect to the pure PVA-TENG, respectively. In addition, MP-TENG exhibited excellent sensing characteristics, a smart home control system was designed in conjunction with a hardware circuit, which captured hand motions and encoded them to generate binary codes to control the on/off state of the indoor home.

Co1.22xNixO4/fMWCNTs-hybrid nanocomposite-based self-adhesive wearable non-enzymatic electrochemical sensor for continuous glucose monitoring in sweat

The development of polymer-based wearable, eco-friendly, and non-invasive sensors has been boosted by the rapid emergence and evolution of soft electronics. However, challenges in the catalysis of glucose and sweat sampling have hampered these advances in the development of efficient wearable glucose sensors. Herein, the porous Co1.22xNixO4 hybrid composite material with interconnecting fMWCNTs, referred to as Co1.22xNixO4/fMWCNTs, was hydrothermally synthesized, and covalently crosslinked into well-patterned, flexible PDMS polymer networks. The hydrophilic fMWCNTs enhanced the anchoring spots for the in situ growth of NiCo–Oxides, which significantly improved the conductive networks and introduced many interface zones with high sensitivity of (1190.9 and 1312.1) µA·mM−1·cm−2, wide linear range of (0.001 − 8.0) mM, low detection limit (20 μM), good long-term stability, and excellent selectivity in alkaline solution. A prototype sensor was fabricated by assembling transparent PDMS film with a hydrophilic membrane of supramolecular double network hydrogel (SP−DN) as adhesive, and breathable substrate for sweat collection. The sensitivity of the calibrated prototype was found to be 1326.83 µA·mM−1·cm−2 with a linear range of ≤ 800 µM, tested in artificial sweat samples. The feasibility of a non-invasive glucose sensor was validated by assembling and testing prototype sensors on multiple volunteers. The SP−DN hydrogel acts as a continuous OH− ion supplier, and makes it possible to oxidize the glucose by metal-oxide-based nano-enzyme. The facile fabrication method and reliability of the results with real blood samples show the potential of the metal-oxide-based sensor prototype as a flexible, and environment-adaptable sensing device.

Flexible multimode sensors based on hierarchical microstructures enable non-destructive grading of fruits in cold chain logistics

In practical applications, flexible pressure sensors must demonstrate adequate sensitivity, durability, and the ability to detect both dynamic and static forces across a wide range. The objective of this study is to develop a flexible dual-mechanism piezoelectric/piezoresistive sensor (FDMPS) based on layered microstructures to enable versatile detection in real fruit sorting operations. The FDMPS consists of an upper layer featuring planar MXene electrodes on a PDMS film, a mid-layer comprising microstructured Ag electrodes on a PVDF-TrFE/Silica gel/ZnO film, and a lower layer with microstructured MXene electrodes on a PDMS film composition. To ensure a secure fit, the three-layer structure is treated with APTES and plasma. All electrodes are produced using a pneumatic direct-write process, while the PDMS and piezoelectric films are created via a spin-coating process, making them suitable for large-scale production. The flexible FDMPS, with a 10 wt% ZnO content, achieves an optimal piezoelectric output of 3.6 V. Additionally, the FDMPS demonstrates excellent linearity (0.997), resistive sensitivity (23.65 kpa−1), and stability (5000 cycles). The incorporation of microstructures significantly enhances the performance of piezoelectric/piezoresistive sensing. Moreover, the FDMPS can accurately measure bending strain rate and angle within the ranges of 0–90°/s (with a sensitivity of 0.014 V/(°·s−1)) and 0–110° (with a sensitivity of 0.216/°), respectively. In a wireless, real-time mode, the FDMPS proves effective in monitoring the reciprocating motion of a robotic arm and assessing fruit ripeness during the grading process. This advancement promotes the development and application of precision agriculture and wearable sensing technologies.