Portable Multiplexed System-Based AD5933 Impedance Analyzer: Toward Multiselective Gas Recognition

Advances on system-on-chip and organic sensors allows the development of miniaturized impedance measurement hardware for gas monitoring in Internet-of-Things (IoT). In this letter, we present the development of miniaturized, multiplexed, and connected platform for impedance spectroscopy. Designed for online measurements and adapted to wireless network architectures, our platform has been tested and optimized to be used for multiselective chemical organic sensor nodes. Our designed circuit is built from low cost and low power consumption microelectronics components providing real time acquisition. The proposed system is based on ESP32 Microcontroller enabling the management of an impedance network analyzer AD5933 (Analog Devices, Norwood, MA, USA) through its I2C interface. Our system benefits from two multiplexer components allowing calibration process and the interface of 15 conductimetric sensors with fast acquisition (less than 90 ms per acquisition). The letter describes the microelectronics design, the impedance response over time, the measurement's sensitivity and accuracy and the testing of the platform with embedded chemical sensors for gas classification and recognition.