Fabrication and Design of Wireless Humidity Sensing Node for Application in IOT System

• Main Authors: Po-Yu Chen, 陳柏宇
• Other Authors: 戴慶良
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/fs4jyq

碩士 === 國立中興大學 === 機械工程學系所 === 106 === This study presents a wireless humidity sensing node which is applied to the Internet of Things (IOT) system. The wireless sensing node is based on the ATmega328p-au chip, and uses ESP8266 Wi-Fi module as the wireless communication device. Fabrication of the humidity sensor uses CMOS(complementary metal oxide semiconductor)-MEMS(micro electromechanical system) technology. Then, the printed circuit board (PCB) is manufactured integrating the electronic components and circuit in the system. The humidity sensor is manufactured using CMOS process, so the sensor achieves the advantages of low cost and small size. The sensor chip is coated with the polyimide on its sensing electrodes. The polyimide adsorbs or releases water vapor, so that the dielectric coefficient changes which causes the capacitance value to change. Compiling the program of the ATmega328p-au chip with Arduino IDE software make that the system has the function of reading the humidity sensor signal and uploading data to the cloud server. The circuit of wireless humidity sensing node is designed EAGLE PCB circuit layout software. After the process of exposure, development and etching, the fabrication of the PCB is completed. Finally, the microcontroller, humidity sensor and other components are soldered on the PCB completing the wireless humidity sensing node.