Design And Realization Of Flexible Inductive Temperature And Humidity Sensor

In recent years,the development of sensors has received extensive attention.Among them,the humidity sensor measures the content of water vapor in the air,and the temperature sensor measures the degree of cold and heat of the object.The temperature and humidity sensor integrating the two functions has a good application prospect.Most traditional temperature and humidity sensors use rigid substrates.With the advancement of flexible electronic technology,people’s demand for flexible products is increasing.The flexible sensor has the advantages of simple manufacturing process,low price,strong flexibility,flexible and diverse structure and easy to carry.In this article,based on the working principle of a planar inductive coil,the hair after high temperature dehydration and degreasing treatment is used as a humidity sensitive material,and a flexible temperature sensor and a flexible humidity sensor are integrated to prepare a flexible inductive temperature and humidity sensor with thermal purification mode.A test system is also built to test the sensor,and the results show that the sensor has good performance.This article first applies the physical characteristics of the inductance value of a planar inductor that changes with the pitch of the coil,and chooses silicon rubber substrate,copper wire and hair as basic materials to design flexible inductive temperature and humidity sensor structure.Secondly,based on the solid mechanics,transfer of dilute substances and solid heat transfer modules of COMSOL software,multi-physics numerical simulations are carried out.The process of adsorption and desorption of water vapor by the humidity-sensitive medium layer of the sensor,the process of thermal purification,and the process of displacement change caused by hygroscopic expansion were simulated.The feasibility of the sensor design was verified and the sensor was prepared.Then,a hardware circuit system with STM32F407ZET6 as the main control chip was built,and the software-driven design of the temperature and humidity signal acquisition module and other functional modules was carried out.The design realizes the thermal purification and data acquisition functions of the temperature and humidity sensor,and displays and saves the data on the host computer.Finally,a sensor testing system was built.The system functions include providing standard temperature and humidity sources,signal acquisition and data processing.The relative performance of the sensor is calibrated,and the results show that the humidity sensitivity of the sensor is 118.92Hz/%RH,the temperature sensitivity is 0.00548V/℃,and the hysteresis is within the range of ±3%RH.And it has the characteristics of wide range,long-term stability,and good linearity of humidity and temperature characteristic curves.Subsequently,the error of the sensor is analyzed and corrected,and the sensor is used to verify the application of human breathing humidity and human skin surface temperature.Experiments show that it has broad development prospects in the field of wearable devices and intelligent medical treatment.