An intelligent human-machine interface (HMI) is a crucial medium for exchanging information between people and electronics. As one of the most important HMI devices, touch screen sensors are widely applied in personal electronics in daily life. However, as the most commonly used touch screen sensor, capacitive sensors can only detect limited kinds of gestures such as touching and sliding. Here, a triboelectric touch-free screen sensor (TSS) is reported for recognizing diverse gestures in a noncontact operating mode by utilizing the charges naturally carried on the human body. Compared with conventional capacitive sensors, the TSS is capable of detecting various gestures such as the drop and lift of finger with different speeds, making a fist, opening palm, and flipping palm with different directions. Based on the TSS, an intelligent noncontact screen control system is further developed, which is used to unlock the smartphone interface by the noncontact operating mode. This research for the first time proposes the concept that taking the human body itself to participate in triboelectric self-powered noncontact sensing and provides a touch-free design concept to develop the next generation of screen sensors. It can alter the usual way that people operating their personal electronics.
Hydraulics provide a unique and widely existed mechanical energy source around us, such as in water or oil pipes, and sewers. Here, a non-contact cylindrical rotating triboelectric nanogenerator (TENG) was developed to harvest the mechanical energy from water flows. Operation of the TENG was based on the non-contact free-rotating between a curved Cu foil and a flexible nanostructured fluorinated ethylene propylene (FEP) polymer film. The free-standing distance between two rotating interfaces avoided abrading of electrode materials. The TENG was able to effectively convert mechanical energy of the water flow into electricity. When driven by water flow, the output voltage and current of the TENG reached 1,670 V and 13.4 μA, respectively. Without any energy storage component, the produced electricity could instantaneously power 12 white light emitting diodes (LEDs) bulbs and a digital timer. This non-contact rotating TENG would provide new opportunities for harvesting energy from many types of hydraulics as a self-sustainable power source for sensing, detection, and protection.
Electronic skin (E‐skin) is an emerging and promising human‐machine interface. Besides skin‐like functions of tactile perception and stretchability, skin‐like comfortabilities, including breathability, moisture permeability, softness, and thermoregulating ability are, also crucial factors for E‐skins. Thermoregulation is one of the most important roles of human skin. People can feel comfortable when their skins are regulated at a certain range of temperature. Moreover, it is a dynamic process according to the surrounding temperature. Current E‐skins do not have the function of dynamically regulating their temperature. Here, a thermoregulating E‐skin (TE‐skin) based on liquid metal as a phase change material with its melting point in the comfortable temperature range of human skin is reported. Compared with conventional E‐skins, the TE‐skin can dynamically termoregulate according to the surrounding temperature through a phase change. Combining with the principle of triboelectric nanogenerator, the TE‐skin is also able to act as a self‐powered sensor. Based on the self‐powered TE‐skin, an intelligent dialing communications system is further developed, which can be used to call a cellphone on human skin. For the first time, this study introduces the dynamic thermoregulating concept to E‐skins and could open up new opportunities for E‐skin developments.
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