Research On Capacitive Flexible Tactile Pressure Sensor And Its Self-power Supply

With the rapid development of the Internet of Things（Io T）and artificial intelligence（AI）,flexible self-powered monitoring products have received increasing attention in practical scenarios due to their portability and foldability.Flexible self-powered monitoring products are mainly divided into two parts:flexible monitoring and energy supply.Among them,the flexible capacitive touch sensor in the flexible monitoring part has low power consumption,fast response,and small drift compared to other sensing mechanisms.However,the sensitivity,testing range,and cost of flexible capacitive sensors still need to be improved.Therefore,there is an urgent need for a new type of flexible capacitive touch pressure sensor that can meet low cost and high sensitivity requirements.At the same time,most of the scenarios where flexible wearable devices are used have requirements for inconvenient charging or long battery life.However,current self-powered modules have issues with insufficient battery life or low energy density,which cannot meet practical demands.Therefore,based on the research and design of sensing,we have integrated flexible batteries and friction generators to form a new self-powered integrated monitoring system.The main research content of this article is as follows:（1）A flexible capacitive pressure sensor with simple structure,low cost,wide working range,good repeatability and high sensitivity was developed.The sensor responds well to both static and dynamic pressures,with high sensitivity and excellent repeatability.The sensor has excellent dynamic response（80ms）and recovery（55ms）.In the pressure range of 0-10k Pa,the sensitivity of the sensor is as high as 0.3199k Pa^-1.The repeatability is good,and it can work stably for 1400 cycles.In addition,the signal of the capacitive pressure sensor has a very high signal-to-noise ratio.The capacitance of the sensor is very large,so no noise reduction or signal amplification is needed in testing and applications.（2）A low-cost ionogel-based microstructured flexible capacitive pressure sensor was designed based on a non-uniform protruding surface microstructured dielectric layer obtained from a sandpaper template.The dielectric layer has excellent mechanical properties（uniaxial tensile strain>3800%）.The application of the double-layer and microstructure results in high sensitivity(3.85k Pa^-1 at pressures below 200k Pa)and a wide pressure range of up to 1250k Pa.This sensor also exhibits excellent mechanical stability,undergoing 2100 compress/release cycles at 4k Pa pressure and 1000compress/release cycles after 7 days without significant performance degradation.The sensor also demonstrates high signal intensity and low noise in a small size,and after a6×6 array experiment,the signal can identify and distinguish the attached shape and specific location without processing,showing great potential for this sensor in electronic skin applications.（3）A flexible and wearable triboelectric（TENG）self-powered sensor system is designed.After the system is powered by a battery in the initial stage,it mainly relies on the electric energy converted by human joint motion to drive the microcontroller to work in the later stage.The developed TENG,as a power source,can be easily fixed on the side of various joints,and can charge a single 100μF capacitor to 3.7V in just about one minute.The strain sensor developed in this chapter can effectively monitor motion deformation,and the stability and practicality of the self-powered sensor system developed in this project were validated through actual applications and network services connections.