IoT Enabled Design of developed hardware for the Graphene Derivatives Based Moisture sensor and Testing under Laboratory Conditions

Abstract

In this study, we created a sensor to measure soil moisture using two graphene derivatives as the sensing materials. To highlight the novelty of our work, we utilized two distinct graphene de-rivatives: graphene oxide (GO) and reduced graphene oxide (rGO), each tested at three concen-trations—0.1 mg, 1 mg, and 10 mg—dispersed in 1 ml of ethanol. These solutions were then drop-casted onto interdigitated electrodes (IDEs) on a printed circuit board (PCB). We evaluated various sensor properties such as sensitivity, selectivity, hysteresis, and stability. Experimental results indicated that for both graphene derivatives, the concentration of 1 mg/1 ml (ethanol) outperformed the other concentrations of 0.1 mg/1 ml and 10 mg/1 ml (ethanol). The sensors showed changes in capacitance in response to soil moisture levels. This change was detected using custom hardware and an oscillator circuit, allowing us to accurately measure soil moisture through the capacitance variation of the GO and rGO sensors.