A Wireless Biosensor for in-Vivo and Real-Time Plant Monitoring for Smart Agriculture

This paper presents a wireless biosensor based on an organic electrochemical transistor and a low-power electronic system, with NB-Iot/Cat-M1 radio interface. The biosensor, implanted in the plant stem, allows the in-vivo evaluation of the concentration of nutrients dissolved as cations in the sap. The electronic circuit enables the real-time monitoring of the plant in the crop. The NB-IoT or Cat-M1 link, both available in the System-in-Package device selected for the proposed system, ensures almost ubiquitous availability of the network link, without severe limitations on the data payload. The low power consumption of the device allows more than 3-month of battery life time, adequate for most seasonal crops. Measurements on KCl solutions showed adequate sensor linearity up to 10-mM K+ concentration, while those performed on a sap of kiwi vines are in agreement with data available in the literature. The final electronic device will have a size of 30mm x 60mm, fitting the requirements of a monitoring device for small plants like tomato.