Electrical Impedance Spectroscopy on 8-channel PSoC-Based Miniaturized Board to Enable Data-Rich Environmental Sensing

Abstract

A variable signal generation and data readout board for miniaturized biochemical and chemical sensors for application in environmental monitoring, agri-food or biomedical applications is presented. The PSoC 5LP-based board is able to deliver DC as well as AC voltage or current of up to 62.5 kHz to a maximum of 8 different sensing fields as well as read back the resulting data and processing it on-board. A sensible use therefore is Electrical Impedance Spectroscopy (EIS). The data received from EIS carries a lot more information about the sensor surface or interaction with the surroundings compared to DC resistance measurements found in literature. Through the frequency-dependent response of the system one receives a much more detailed description of the sensor-analyte-interaction. This enables the use of more complex biological or chemical sensors as well as mixed sensors arrays. The system is evaluated using a gas sensor featuring an array of 8 sensor fields with different μ-dispensed functionalities and following algorithm-assisted data evaluation which can later be integrated on chip level.