Batteryless Soil EIS Sensor Powered by Microbial Fuel Cell

Batteryless devices are becoming fundamental to fostering self-sustainable and environmentally friendly Internet of Things (IoT) growth. In precision agriculture and, more broadly, for environmental monitoring, battery-less IoT systems are particularly effective due to their low environmental impact and maintenance cost. In this paper, we present the study of a battery-less Plant-Microbial Fuel Cells based IoT architecture for plant growth and health monitoring by exploiting electrochemical impedance spectroscopy. Plant-Microbial Fuel Cells – and, in turn, the plant itself – health and status can be assessed starting from specific features extracted from Electrochemical Impedance Spectroscopy (EIS) data. The proposed system exploits an ultra-low-power integrated electrochemical sensor analog front-end providing both DC polarization and EIS measurements. The system can self-sustain its operations by exploiting the same energy harvested from the monitored PMFC. Finally, a LoRa transceiver is in charge of transmitting status updates remotely. Results show that for a sweep of 19 points from 21.3 mHz to 21.8 kHz the overall required energy consumption is equal to 4.38 J.