Query: wearable integrated sensor

title: Fully integrated wearable pressure sensor array enabled by highly sensitive textile based capacitive ionotronic devices
abstract: Recently, textile based pressure sensors have gained considerable interest in the field of wearable electronics due to their wide range of applicability and good scalability. Despite recent progress, however, urgent challenges remain to develop a fully integrated textile sensor array with highly sensitive multi sensing capability and low power consumption. Here, we demonstrate a highly sensitive capacitive ionotronic (CIT) pressure sensor array using high k ion gel (IG) film for implementation of textile based electronic systems. With a composition and thickness optimized IG film, CIT pressure sensors with high sensitivity up to 308 nF kPa 1 and relatively good stability was successfully obtained. In addition, based on mechanical simulations using finite element method, it was found that the pressure dependent contact area variation between multifilament fiber electrodes and the IG film played the dominant role in capacitance change rather than the thickness change of the IG film. Furthermore, a 3 x 3 CIT pressure sensor system is implemented on a large area textile substance with multi point detection capability, demonstrating a textile based pressure monitoring system integrated with a pressure variable multi color light emitting diode array.

title: A data driven machine learning integrated wearable medical sensor framework for elderly care service
abstract: Recently, Wearable Medical Devices (WMDs) is a promising medical technology to improve patient treatment in various medical perspectives. However, the traditional model driven framework faces challenges on narrow reconstruction ratio and compression ratio due to improper measurement of signals in sensors. In this research, a Machine Learning assisted Integrated Data driven framework (MLA IDDF) that can acquire signal features based on personalized characteristics from elderly patients to improve compressive sensing performance with a reduced number of measurements for precise model. The system coordinates the collection and processing of raw sensor data from a variety of sources in a common information database. MLA IDDF develops semantic models to describe patient's conditions, and decision making mechanisms based on the interpretation of collected data that provides accurate observations about elderly patients. The Simulation analysis at the lab scale shows the performance of the system and user satisfaction assessments confirmed that the system is superior to other conventional systems.

title: Personalized Human Activity Recognition Based on Integrated Wearable Sensor and Transfer Learning
abstract: Human activity recognition (HAR) based on the wearable device has attracted more attention from researchers with sensor technology development in recent years. However, personalized HAR requires high accuracy of recognition, while maintaining the model's generalization capability is a major challenge in this field. This paper designed a compact wireless wearable sensor node, which combines an air pressure sensor and inertial measurement unit (IMU) to provide multi modal information for HAR model training. To solve personalized recognition of user activities, we propose a new transfer learning algorithm, which is a joint probability domain adaptive method with improved pseudo labels (IPL JPDA) This method adds the improved pseudo label strategy to the JPDA algorithm to avoid cumulative errors due to inaccurate initial pseudo labels. In order to verify our equipment and method, we use the newly designed sensor node to collect seven daily activities of 7 subjects. Nine different HAR models are trained by traditional machine learning and transfer learning methods. The experimental results show that the multi modal data improve the accuracy of the HAR system. The IPL JPDA algorithm proposed in this paper has the best performance among five HAR models, and the average recognition accuracy of different subjects is 93.2%

title: An integrated wearable strain, temperature and humidity sensor for multifunctional monitoring
abstract: Explosive growth in demand for wearable devices has promoted the development of smart materials with multifunctional performances. Flexible flax fabric (FF) coated with CNT and nickel serving as multifunctional sensor are prepared through a cost effective dip coating and electroless deposition technology. Biocompatible dopamine film self polymerized on CNT surface effectively enhances the interfacial bonding strength between CNT and nickel coating. The conductive composite function as a strain sensor exhibits distinctive negative gauge factor and commendable repeatability during cyclic loading and unloading process. As a temperature sensor, the conductive composite also shows a negative temperature coefficient dependence and prominent behaviors including admirable sensitivity 2.96% and long term stability. The electrical response of the conductive composite is linear correlation with relative humidity (RH) ranging from 11% RH to 94% RH, demonstrating a relatively high sensitivity (4.73) In addition, even after suffering from acid, neutral and alkaline atmosphere for a period, the humidity sensing response is still satisfying, which illustrates the outstanding anti corrosion properties. Therefore, the as prepared conductive composite integrated with strain, temperature and humidity capabilities endows immense potential in wearable electronics.

title: A Wearable Sensor Based on Gold Nanowires/Textile and Its Integrated Smart Glove for Motion Monitoring and Gesture Expression

title: A Soft Wearable and Fully Textile Piezoresistive Sensor for Plantar Pressure Capturing
abstract: The trends of wearable health monitoring systems have led to growing demands for gait capturing devices. However, comfortability and durability under repeated stress are still challenging to achieve in existing sensor enabled footwear. Herein, a flexible textile piezoresistive sensor (TPRS) consisting of a reduced graphene oxide (rGO) cotton) fabric electrode and an Ag fabric circuit electrode is proposed. Based on the mechanical and electrical properties of the two fabric electrodes, the TPRS exhibits superior sensing performance, with a high sensitivity of 3.96 kPa 1 in the lower pressure range of 0 36 kPa, wide force range (0 100 kPa) fast response time (170 ms) remarkable durability stability (1000 cycles) and detection ability in different pressures ranges. For the prac tical application of capturing plantar pressure, six TPRSs were mounted on a flexible printed circuit board and integrated into an insole. The dynamic plantar pressure distribution during walking was derived in the form of pressure maps. The proposed fully textile piezoresistive sensor is a strong candidate for next generation plantar pressure wearable monitoring devices.

title: A Wearable Body Condition Sensor System with Wireless Feedback Alarm Functions.
abstract: Emerging feedback systems based on tracking body conditions can save human lives. In particular, vulnerable populations such as disabled people, elderly, and infants often require special care. For example, the high global mortality of infants primarily owing to sudden infant death syndrome while sleeping makes request for extraordinary attentions in neonatal intensive care units or daily lives. Here, a versatile laser induced graphene (LIG) based integrated flexible sensor system, which can wirelessly monitor the sleeping postures, respiration rate, and diaper moisture with feedback alarm notifications, is reported. A tilt sensor based on confining a liquid metal droplet inside a cavity can track at least 18 slanting orientations. A rapid and scalable laser direct writing method realizes LIG patterning in both the in plane and out of plane configurations as well as the formation of nonstick conductive structures to the liquid metal. By rationally merging the LIG based tilt, strain, and humidity sensors on a thin flexible film, the multimodal sensor device is applied to a diaper as a real time feedback tracking system of the sleeping posture, respiration, and wetness toward secure and comfortable lives. User friendly interfaces, which incorporate alarming functions, provide timely feedback for caregivers tending to vulnerable populations with limited self care capabilities.

title: Review of 3D printing technologies for wearable and implantable bio integrated sensors.
abstract: Thin film microfabrication based bio integrated sensors are widely used for a broad range of applications that require continuous measurements of biophysical and biochemical signals from the human body. Typically, they are fabricated using standard photolithography and etching techniques. This traditional method is capable of producing a precise, thin, and flexible bio integrated sensor system. However, it has several drawbacks, such as the fact that it can only be used to fabricate sensors on a planar surface, it is highly complex requiring specialized high end facilities and equipment, and it mostly allows only 2D features to be fabricated. Therefore, developing bio integrated sensors via 3D printing technology has attracted particular interest. 3D printing technology offers the possibility to develop sensors on nonplanar substrates, which is beneficial for noninvasive bio signal sensing, and to directly print on complex 3D nonplanar organ structures. Moreover, this technology introduces a highly flexible and precisely controlled printing process to realize patient specific sensor systems for ultimate personalized medicine, with the potential of rapid prototyping and mass customization. This review summarizes the latest advancements in 3D printed bio integrated systems, including 3D printing methods and employed printing materials. Furthermore, two widely used 3D printing techniques are discussed, namely, ex situ and in situ fabrication techniques, which can be utilized in different types of applications, including wearable and smart implantable biosensor systems.

title: A fully integrated wearable electronic device with breathable and washable properties for long term health monitoring
abstract: The fully integrated wearable electronics have recently found widespread applications in long term health monitoring, where one major challenge is to develop substrate materials with excellent breathability and washability. In this work, we developed a fully integrated wearable electronic device with breathable and washable properties through a facile and scalable paradigm. We directly mixed hydrophilic graphene oxide with hydrophilic cellulose fibers to ensure that graphene nanosheets uniformly spread all over the paper matrix. Then laser reduction was applied to fabricate a graphene cellulose temperature sensor (LRG TS) and thermal reduction to make a graphene cellulose pressure sensor (TRG PS) both of which were then connected with a flexible printed circuit board (FPCB) to form a fully integrated wearable electronic device with results readable by a mobile phone through Bluetooth. The excellent breathability, attributed to the unique 3D hierarchical porous structure of the e paper, lays a solid foundation for long term monitoring as demonstrated in rabbit skin in vitro. Besides, it can endure long term soaking in water and multiple washing drying cycles without compromising structural integrity and functional performance, as shown by sensing of body temperature and human motion. The developed device with these two unparalleled properties holds great promise for versatile wearable electronics applications in personal healthcare monitoring.

title: Design and Fabrication of a New Wearable Pressure Sensor for Blood Pressure Monitoring
abstract: In recent years, research into the field of materials for flexible sensors and fabrication techniques directed towards wearable devices has helped to raise awareness of the need for new sensors with healthcare applicability. Our goal was to create a wearable flexible pressure sensor that could be integrated into a clinically approved blood pressure monitoring device. The sensor is built from a microfluidic channel encapsulated between two polymer layers, one layer being covered by metal transducers and the other being a flexible membrane containing the microfluidic channel, which also acts as a sealant for the structure. The applied external pressure deforms the channel, causing changes in resistance to the microfluidic layer. Electrical characterization has been performed in 5 different configurations, using alternating current (AC) and (DC) direct current measurements. The AC measurements for the fabricated pressure sensor resulted in impedance values at tens of hundreds of kOhm. Our sensor proved to have a high sensitivity for pressure values between 0 and 150 mm Hg, being subjected to repeatable external forces. The novelty presented in our work consists in the unique technological flow for the fabrication of the flexible wearable pressure sensor. The proposed miniaturized pressure sensor will ensure flexibility, low production cost and ease of use. It is made of very sensitive microfluidic elements and biocompatible materials and can be integrated into a wearable cuffless device for continuous blood pressure monitoring.