Low Cost Wireless Data Acquisition System for CMOS MEMS Sensor

This present study is to focus and evaluate the performance of a complementary metal–oxide–semiconductor (CMOS) micro-electro-mechanical systems (MEMS) piezoresistive sensor with different pressure ranges under vacuum condition using a self-developed low-cost wireless data acquisition system (WDAQ). The pressure sensor was designed and fabricated using UMC 0.18 µm 1P6M standard CMOS process and MEMS technology. The sensing elements of the piezoresistors are polysilicon and they are integrated with CMOS circuits to complete the Wheatstone bridge and sensor system. The testing of pressure sensor was done with a vacuum pressure range of 0–100 kPa. The output signals were extracted using a commercial data acquisition system DAQ970A and compared with the self-developed ESP8266-based WDAQ. The results extracted using both the DAQ and WDAQ showed good linearity response over the pressure range with a sensitivity of 6.878 µV/V/psi, and the average efficiency of WDAQ was found to be 98% compared to the DAQ970A. The proposed WDAQ is a low-cost solution for remote data collection and transmission. The WDAQ system is built using ESP8266 WIFI module, coupled with an Arduino Nano. Java small object notation (JSON) is used to send data from Arduino nano to ESP8266 using the serial communication protocol, allowing for the transfer of data to Google Sheets using application programming interface (API). The system is enclosed in a package, making it suitable for wind turbines, flapping wings and other harsh environments. The WDAQ provides the required operating voltage to the CMOS MEMS sensor which makes it a self-reliant system. The design, implementation, and performance assessment of the WDAQ system are all thoroughly depicted herein. The work also concentrates on swarm networks to send data to servers in areas where there is limited network connectivity.