Design of wireless soil moisture sensor powered by bacteria charged paper battery.

Lack of information and dependence on unscientific techniques for measuring soil moisture has resulted in water loss and reduced crop yield for smallholder farmers in developing countries. Existing sensors are expensive, eco-unfriendly, and require an external power source hence cannot be used in off-grid and rural areas. The objective of this work is to design a wireless low-cost, biodegradable, and environment-friendly paper-based soil moisture sensor powered by microbes present in the soil which will transmit this moisture data to smartphones. The expected outcome of this work is the real-time soil moisture monitoring system accessible in off-grid areas based on microbial fuel cells (MFC). The fundamental assumption here is that the current generated by MFC and signal sent by the flexible near field communication (NFC) tag will be a function of soil moisture. This document describes the empirical procedure followed to execute this study. A lab-scale proof of concept is presented where the current is generated by a paper battery fabricated using cellulose paper and conductive ink along with microbes present in the soil and nitrates. Future plans of embedding the paper battery with NFC tags for designing soil moisture sensor using MFC technology is also presented.