A highly sensitive piezoresistive sensor based on CNT-rGO aerogel for human motion detection

2021 ◽  
pp. 002199832110201
Author(s):  
Hao Zhu ◽  
Shengping Dai ◽  
Xiaoshuang Zhou ◽  
Xu Dong ◽  
Yaoyao Jiang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Sensitivity ◽  
Fast Response ◽  
Human Motion ◽  
Body Motion ◽  
Highly Active ◽  
Human Motion Detection ◽  
Piezoresistive Sensor ◽  
Stress Changes ◽  
Redox Method

In recent years, Flexible sensors have emerged as a highly active field due to their promising applications in artificial intelligence systems and wearable health care devices. However, achieving a high sensitivity in a wide pressure range is still a challenge. Here, a three-dimensional network structure CNT-rGO aerogels were prepared by a hydrothermal redox method, which can effectively enhance the mechanical strength and enrich the electrical conductivity paths. Moreover, the CNT–rGO aerogel-based piezoresistive sensor exhibited a fast response time (∼300 ms), wide working range (0∼3.5 kPa−1), high sensitivity (11.8 kPa−1), and good stability (∼2000 cycles). So the piezoresistive sensor can be employed to monitor and distinguish both large motions (e.g., weight placed on the aerogel) and subtle motions (e.g., pronounce and pulse), which shows potential applications in measuring pressure distribution, distinguishing tiny stress changes, and monitoring human body motion.

Highly sensitive and stretchable strain sensors based on chopped carbon fibers sandwiched between silicone rubber layers for human motion detections

2019 ◽  
Vol 54 (3) ◽  
pp. 423-434 ◽  
Author(s):  
MB Azizkhani ◽  
Sh Rastgordani ◽  
A. Pourkamali Anaraki ◽  
J Kadkhodapour ◽  
B Shirkavand Hadavand
Keyword(s):  
Carbon Fibers ◽  
Motion Detection ◽  
Silicone Rubber ◽  
Low Cost ◽  
High Sensitivity ◽  
Human Motion ◽  
Strain Sensors ◽  
Body Motion ◽  
Gauge Factor ◽  
Human Motion Detection

Tuning the electromechanical performance in piezoresistive composite strain sensors is primarily attained through appropriately employing the materials system and the fabrication process. High sensitivity along with flexibility in the strain sensing devices needs to be met according to the application (e.g. human motion detection, health and sports monitoring). In this paper, a highly stretchable and sensitive strain sensor with a low-cost fabrication is proposed which is acquired by embedding the chopped carbon fibers sandwiched in between silicone rubber layers. The electrical and mechanical features of the sensor were characterized through stretch/release loading tests where a considerably high sensitivity (the gauge factor about 100) was observed with very low hysteresis. This implies high strain reversibility (i.e. full recovery in each cycle) over 700 loading cycles. Moreover, the sensors exhibited ultra-high stretchability (up to ∼300% elongation) in addition to a low stiffness meaning minimal mechanical effects induced by the sensor for sensitive human motion monitoring applications including large and small deformations. The results suggest the promising capability of the present sensor in reflecting the human body motion detection.

Three-Dimensional Graphene-Based Composite for Elastic Strain Sensor Applications

MRS Advances ◽  
2016 ◽  
Vol 1 (34) ◽  
pp. 2415-2420 ◽  
Author(s):  
Jinhui Li ◽  
Guoping Zhang ◽  
Rong Sun ◽  
C. P. Wong
Keyword(s):  
Flexible Electronics ◽  
Performance Monitoring ◽  
Three Dimensional ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Human Motion ◽  
Strain Sensors ◽  
Sensor Applications ◽  
Human Motion Detection ◽  
Highly Stretchable

ABSTRACTFlexible electronics has emerged as a very promising field, in particular,wearable, bendable, and stretchable strain sensors with high sensitivity which could be used for human motion detection, sports performance monitoring, etc. In this paper, a highly stretchable and sensitive strain sensor composed of reduced graphene oxide foam and elastomer composite is fabricated by assembly and followed by a polymer immersing process. The strain sensor has demonstrated high stretchability and sensitivity. Furthermore, the device was employed for gauging muscle-induced strain which results in high sensitivity and reproducibility. The developed strain sensors showed great application potential in fields of biomechanical systems.

scholarly journals Antibacterial, Flexible, and Conductive Membrane Based on MWCNTs/Ag Coated Electro-Spun PLA Nanofibrous Scaffolds as Wearable Fabric for Body Motion Sensing

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 120 ◽  
Author(s):  
Lu Gan ◽  
Aobo Geng ◽  
Ying Wu ◽  
Linjie Wang ◽  
Xingyu Fang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Silver Nanoparticles ◽  
Three Dimensional ◽  
Antibacterial Properties ◽  
Human Motion ◽  
Body Motion ◽  
Body Parts ◽  
Motion Sensing ◽  
Nanofibrous Scaffolds ◽  
Conductive Membrane

In the present study, flexible and conductive nanofiber membranes were prepared by coating PLA nanofibrous scaffolds with carbon nanotubes and silver nanoparticles. The morphology and structure of the prepared membrane was characterized, as well as its mechanical properties, electrical sensing behavior during consecutive stretching-releasing cycles and human motion detecting performance. Furthermore, the antibacterial properties of the membrane was also investigated. Due to the synergistic and interconnected three-dimensional (3D) conductive networks, formed by carbon nanotubes and silver nanoparticles, the membrane exhibited repeatable and durable strain-dependent sensitivity. Further, the prepared membrane could accurately detect the motions of different body parts. Accompanied with promising antibacterial properties and washing fastness, the prepared flexible and conductive membrane provides great application potential as a wearable fabric for real-time body motion sensing.

scholarly journals Privacy-Preserved Fall Detection Method with Three-Dimensional Convolutional Neural Network Using Low-Resolution Infrared Array Sensor

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5957
Author(s):  
Shigeyuki Tateno ◽  
Fanxing Meng ◽  
Renzhong Qian ◽  
Yuriko Hachiya
Keyword(s):  
Neural Network ◽  
Nursing Homes ◽  
Convolutional Neural Network ◽  
Motion Detection ◽  
Three Dimensional ◽  
Fall Detection ◽  
Human Motion ◽  
Portable Devices ◽  
Human Motion Detection ◽  
Infrared Array

Due to the rapid aging of the population in recent years, the number of elderly people in hospitals and nursing homes is increasing, which results in a shortage of staff. Therefore, the situation of elderly citizens requires real-time attention, especially when dangerous situations such as falls occur. If staff cannot find and deal with them promptly, it might become a serious problem. For such a situation, many kinds of human motion detection systems have been in development, many of which are based on portable devices attached to a user’s body or external sensing devices such as cameras. However, portable devices can be inconvenient for users, while optical cameras are affected by lighting conditions and face privacy issues. In this study, a human motion detection system using a low-resolution infrared array sensor was developed to protect the safety and privacy of people who need to be cared for in hospitals and nursing homes. The proposed system can overcome the above limitations and have a wide range of application. The system can detect eight kinds of motions, of which falling is the most dangerous, by using a three-dimensional convolutional neural network. As a result of experiments of 16 participants and cross-validations of fall detection, the proposed method could achieve 98.8% and 94.9% of accuracy and F1-measure, respectively. They were 1% and 3.6% higher than those of a long short-term memory network, and show feasibility of real-time practical application.

scholarly journals Patterned Metal/Polymer Strain Sensor with Good Flexibility, Mechanical Stability and Repeatability for Human Motion Detection

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 472 ◽  
Author(s):  
Xu Zheng ◽  
Qing Wang ◽  
Jinjin Luan ◽  
Yao Li ◽  
Ning Wang
Keyword(s):  
Nanoimprint Lithography ◽  
Mechanical Stability ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Human Motion ◽  
Polymer Composite Material ◽  
Metallic Surface ◽  
Smart Systems ◽  
Human Motion Detection ◽  
Metal Polymer

Wearable health monitoring smart systems based on flexible metal films are considered to be the next generation of devices for remote medical practice. However, cracks on the metallic surface of the films and difficulty in repeatability are the key issues that restrict the application of such wearable strain sensors. In this work, a flexible wearable strain sensor with high sensitivity and good repeatability was fabricated based on a patterned metal/polymer composite material fabricated through nanoimprint lithography. The mechanical properties were measured through cyclic tension and bending loading. The sensor exhibited a small ΔR/R0 error line for multiple test pieces, indicating the good mechanical stability and repeatability of the fabricated device. Moreover, the sensor possesses high sensitivity with gauge factors of 10 for strain less than 50% and 40 for strain from 50% to 70%. Various activities were successfully detected in real-time, such as swallowing, closing/opening of the mouth, and multi-angle bending of elbow, which illustrates the proposed sensor’s potential as a wearable device for the human body.

scholarly journals Flexible Ecoflex®/Graphene Nanoplatelet Foams for Highly Sensitive Low-Pressure Sensors

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4406
Author(s):  
Marco Fortunato ◽  
Irene Bellagamba ◽  
Alessio Tamburrano ◽  
Maria Sabrina Sarto
Keyword(s):  
High Performance ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Cost Effective ◽  
Low Pressure ◽  
Human Motion ◽  
Compression Tests ◽  
Piezoresistive Sensors ◽  
Human Motion Detection ◽  
Pressure Regime

The high demand for multifunctional devices for smart clothing applications, human motion detection, soft robotics, and artificial electronic skins has encouraged researchers to develop new high-performance flexible sensors. In this work, we fabricated and tested new 3D squeezable Ecoflex® open cell foams loaded with different concentrations of graphene nanoplatelets (GNPs) in order to obtain lightweight, soft, and cost-effective piezoresistive sensors with high sensitivity in a low-pressure regime. We analyzed the morphology of the produced materials and characterized both the mechanical and piezoresistive response of samples through quasi-static cyclic compression tests. Results indicated that sensors infiltrated with 1 mg of ethanol/GNP solution with a GNP concentration of 3 mg/mL were more sensitive and stable compared to those infiltrated with the same amount of ethanol/GNP solution but with a lower GNP concentration. The electromechanical response of the sensors showed a negative piezoresistive behavior up to ~10 kPa and an opposite trend for the 10–40 kPa range. The sensors were particularly sensitive at very low deformations, thus obtaining a maximum sensitivity of 0.28 kPa−1 for pressures lower than 10 kPa.

scholarly journals A Soft Wearable and Full Textile Piezoresistive Sensor for Plantar Pressure Capturing

2020 ◽  
Author(s):  
Yongsong Tan ◽  
Kamen Ivanov ◽  
Zhanyong Mei ◽  
Hui Li ◽  
Ludwig Lubich ◽  
...  
Keyword(s):  
Plantar Pressure ◽  
Printed Circuit Board ◽  
High Sensitivity ◽  
Fast Response ◽  
Circuit Board ◽  
Plantar Pressure Distribution ◽  
Piezoresistive Sensor ◽  
Flexible Printed Circuit ◽  
Circuit Electrode ◽  
Force Range

Abstract The trends of health wearable monitoring system have led to growing demands for gait capturing device. The comfortability and durability under repeated stress in the existing sensor-enabled footwear are still problems. Herein, a flexible textile piezoresistive sensor (TPRS) consisting of rG-cotton fabric electrode and Ag fabric circuit electrode is prepared. Based on the mechanical and electrical properties of two fabric electrodes, the TPRS exhibits superior sensing performance, which includes high sensitivity of 3.96kPa-1 in the lower pressure range of 0-36kPa, wide force range (0-800 kPa), fast response time (170 ms), remarkable durability stability (1000 cycles) and dection ability in differrent pressures. For practical application of capturing plantar pressure, six TPRSs are mounted on a flexible printed circuit board and integrated into an insole. The dynamic plantar pressure distribution is displayed through drawing the pressure maps during walking. The proposed full textile piezoresistive sensor is a strong candidate for next-generation plantar pressure wearables monitoring device.

scholarly journals Highly Sensitive and Stretchable c-MWCNTs/PPy Embedded Multidirectional Strain Sensor Based on Double Elastic Fabric for Human Motion Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2333
Author(s):  
Huiying Shen ◽  
Huizhen Ke ◽  
Jingdong Feng ◽  
Chenyu Jiang ◽  
Qufu Wei ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Human Motion ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
Synovial Joint ◽  
Human Motion Detection

Owing to the multi-dimensional complexity of human motions, traditional uniaxial strain sensors lack the accuracy in monitoring dynamic body motions working in different directions, thus multidirectional strain sensors with excellent electromechanical performance are urgently in need. Towards this goal, in this work, a stretchable biaxial strain sensor based on double elastic fabric (DEF) was developed by incorporating carboxylic multi-walled carbon nanotubes(c-MWCNTs) and polypyrrole (PPy) into fabric through simple, scalable soaking and adsorption-oxidizing methods. The fabricated DEF/c-MWCNTs/PPy strain sensor exhibited outstanding anisotropic strain sensing performance, including relatively high sensitivity with the maximum gauge factor (GF) of 5.2, good stretchability of over 80%, fast response time < 100 ms, favorable electromechanical stability, and durability for over 800 stretching–releasing cycles. Moreover, applications of DEF/c-MWCNTs/PPy strain sensor for wearable devices were also reported, which were used for detecting human subtle motions and dynamic large-scale motions. The unconventional applications of DEF/c-MWCNTs/PPy strain sensor were also demonstrated by monitoring complex multi-degrees-of-freedom synovial joint motions of human body, such as neck and shoulder movements, suggesting that such materials showed a great potential to be applied in wearable electronics and personal healthcare monitoring.

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