A Real-Time IoT-Based Nitrate Sensing System Using Interdigital Transducer

Abstract

Lack of low-cost systems makes quality drinking water inaccessible to common people. Nitrate is considered as one of the critical parameters in water quality. Being colorless and odorless it is difficult to find nitrate with human senses. An Internet of Things (IoT)-based smart nitrate sensor design is presented here. The portable system makes use of the impedance change of interdigital transducers (IDT) with nitrate concentration in solution. The phase change of the signal coming from the sensor due to impedance change with nitrate concentration is converted to change in the positive edge of the square wave. The microcontroller can further manipulate the incoming signal to measure the impedance change in the water to quantify the nitrate content. A NodeMCU-based low-cost water quality tester with results displaying on mobile is presented in this paper. The inclusion of Wi-Fi-based IoT establishes the possibility of a distributed monitoring system.