Smart garments for monitoring physiological and biomechanical signals of the human body are key sensors for personalized healthcare. However, they typically require bulky battery packs or have to be ...plugged into an electric plug in order to operate. Thus, a smart shirt that can extract energy from human body motions to run body-worn healthcare sensors is particularly desirable. Here, we demonstrated a metal-free fiber-based generator (FBG) via a simple, cost-effective method by using commodity cotton threads, a polytetrafluoroethylene aqueous suspension, and carbon nanotubes as source materials. The FBGs can convert biomechanical motions/vibration energy into electricity utilizing the electrostatic effect with an average output power density of ∼0.1 μW/cm2 and have been identified as an effective building element for a power shirt to trigger a wireless body temperature sensor system. Furthermore, the FBG was demonstrated as a self-powered active sensor to quantitatively detect human motion.
Versatile and low‐cost manufacturing processes/materials are essential for the development of paper electronics. Here, a direct‐write laser patterning process is developed to make conductive ...molybdenum carbide–graphene (MCG) composites directly on paper substrates. The hierarchically porous MCG structures are converted from fibrous paper soaked with the gelatin‐mediated inks containing molybdenum ions. The resulting Mo3C2 and graphene composites are mechanically stable and electrochemically active for various potential applications, such as electrochemical ion detectors and gas sensors, energy harvesters, and supercapacitors. Experimentally, the electrical conductivity of the composite is resilient to mechanical deformation with less than 5% degradation after 750 cycles of 180° repeated folding tests. As such, the direct laser conversion of MCGs on papers can be applicable for paper‐based electronics, including the 3D origami folding structures.
A direct‐write laser‐patterning process to induce molybdenum carbide–graphene composites on paper substrates is developed by using inks of molybdenum ions and gelatin media with potential applications in 3D foldable energy generators, electrochemical sensors, and supercapacitors.
A smart face mask that can conveniently monitor breath information is beneficial for maintaining personal health and preventing the spread of diseases. However, some challenges still need to be ...addressed before such devices can be of practical use. One key challenge is to develop a pressure sensor that is easily triggered by low pressure and has excellent stability as well as electrical and mechanical properties. In this study, a wireless smart face mask is designed by integrating an ultrathin self‐powered pressure sensor and a compact readout circuit with a normal face mask. The pressure sensor is the thinnest (totally compressed thickness of ≈5.5 µm) and lightest (total weight of ≈4.5 mg) electrostatic pressure sensor capable of achieving a peak open‐circuit voltage of up to ≈10 V when stimulated by airflow, which endows the sensor with the advantage of readout circuit miniaturization and makes the breath‐monitoring system portable and wearable. To demonstrate the capabilities of the smart face mask, it is used to wirelessly measure and analyze the various breath conditions of multiple testers.
The thinnest (totally compressed thickness of ≈5.5 µm) and lightest (total weight of ≈4.5 mg) self‐powered pressure sensor developed can output a peak open‐circuit voltage up to ≈10 V when stimulated by airflow. A portable/wearable smart face mask is obtained based on the sensor and is used for wireless monitoring and analysis of various breath conditions from multiple testers.
Real‐time and continuous monitoring of physiological signals is essential for mobile health, which is becoming a popular tool for efficient and convenient medical services. Here, an active pulse ...sensing system that can detect the weak vibration patterns of the human radial artery is constructed with a sandwich‐structure piezoelectret that has high equivalent piezoelectricity. The high precision and stability of the system result in possible medical assessment applications, including the capability to identify common heart problems (such as arrhythmia); the feasibility to conduct pulse palpation measurements similar to well‐trained doctors in Traditional Chinese Medicine; and the possibility to measure and read blood pressure.
A piezoelectret‐based human pulse sensing system with excellent sensitivity and stability is applied for medical assessments. Pulse waves classification, arrhythmia diagnosis, blood pressure measurement, and imitation of three‐finger pulse palpation in Traditional Chinese Medicine are successfully demonstrated, indicating the potential application in wearable mobile health.
Self‐powered and wearable electronics, which are away from the problems of batteries, can provide the sustainable and comfortable interactive service for people. In this work, cellular polypropylene ...piezoelectret, which is with excellent physical and electrical properties, is utilized to build the human body energy harvesting and self‐powered human health monitoring systems. The cellular polypropylene piezoelectret flexible generator can reach a maximum peak power density of ≈52.8 mW m−2. Simultaneously, self‐powered human body biological signals detecting sensors are demonstrated to detect the human physiological signals, such as coughing action and arterial pulses. This study strongly indicates the great compatibility and potential applications in human healthy monitoring may pave a new developing way for portable and wearable electronics systems.
Simple‐structured and efficient human body energy harvesting and self‐powered human health monitoring systems are demonstrated basing on the cellular polypropylene piezoelectret. A maximum peak power density of ≈52.8 mW m−2 is obtained and human physiological signals, such as coughing action and arterial pulse, are detected. These systems develop a new way for self‐powered and wearable electronics.
A variety of autonomous oscillations in nature such as heartbeats and some biochemical reactions have been widely studied and utilized for applications in the fields of bioscience and engineering. ...Here, we report a unique phenomenon of moisture-induced electrical potential oscillations on polymers, poly(2-(methacryloyloxy)ethyl dimethyl-(3-sulfopropyl) ammonium hydroxide-co-acrylic acid), during the diffusion of water molecules. Chemical reactions are modeled by kinetic simulations while system dynamic equations and the stability matrix are analyzed to show the chaotic nature of the system which oscillates with hidden attractors to induce the autonomous surface potential oscillation. Using moisture in the ambient environment as the activation source, this self-excited chemoelectrical reaction could have broad influences and usages in surface-reaction based devices and systems. As a proof-of-concept demonstration, an energy harvester is constructed and achieved the continuous energy production for more than 15,000 seconds with an energy density of 16.8 mJ/cm
. A 2-Volts output voltage has been produced to power a liquid crystal display toward practical applications with five energy harvesters connected in series.
Harvest mechanical energy with variable frequency and amplitude in our environment for building self-powered systems is an effective and practically applicable technology to assure the independently ...and sustainable operation of mobile electronics and sensor networks without the use of a battery or at least with extended life time. In this study, we demonstrated a novel and simple arch-shaped flexible triboelectric nanogenerator (TENG) that can efficiently harvesting irregular mechanical energy. The mechanism of the TENG was intensively discussed and illustrated. The instantaneous output power of single TENG device can reach as high as∼4.125mW by a finger typing, which is high enough to instantaneously drive 50 commercial blue LEDs connected in series, demonstrating the potential application of the TENG for self-powered systems and mobile electronics.
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► A novel and simple arch-shaped triboelectric nanogenerator is invented that can efficiently used for harvesting irregular mechanical energy. ► Instantaneous output power of single device can reach as high as ∼4.125mW which is enough to instantaneously drive 50 commercial blue LEDs connected in series. ► By conjunction with a transformer, the device can power the wireless infrared sensor system.
A type of strain sensor with high tolerable strain based on a ZnO nanowires/polystyrene nanofibers hybrid structure on a polydimethylsiloxane film is reported. The novel strain sensor can measure and ...withstand high strain and demonstrates good performance on rapid human‐motion measurements. In addition, the device could be driven by solar cells. The results indicate that the device has potential applications as an outdoor sensor system.
Over the past few years, the rapid development of tactile sensing technology has contributed significantly to the realization of intuitional touch control and intelligent human-machine interaction. ...Apart from physical touch or pressure sensing, proximity sensing as a complementary function can extend the detection mode of common single functional tactile sensors. In this work, we present a transparent, matrix-structure dual functional capacitive sensor which integrates the capability of proximity and pressure sensing in one device, and the excellent spatial resolution offered by the isolated response of capacitive pixels enables us to realize precise location identification of approaching objects and loaded pressure with fast response, high stability and high reversibility.
This paper considers the finite-time dynamic tracking control for parallel robots with uncertainties and input saturation via a finite-time nonsingular terminal sliding mode control scheme. A ...disturbance observer is designed to estimate the lumped disturbance in the dynamic model of the parallel robot, including modeling errors, friction and external disturbance. By introducing the fractional exponential powers into the existing asymptotic convergent auxiliary system, a novel finite-time convergent auxiliary system is constructed to compensate for input saturation. The finite-time nonsingular terminal sliding mode control is proposed based on the disturbance estimation and the state of the novel auxiliary system, so that the convergence performance, control accuracy and robustness are improved. Due to the estimation and compensation for the lumped disturbance, the inherent chattering characteristic of sliding mode control can be alleviated by reducing the control gain. The finite-time stability of the closed-loop system is proved with Lyapunov theory. Finally, simulation and experimental research on the dynamic control of a conveying parallel robot are carried out to verify the effectiveness of the proposed method.
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