Performance Evaluation of a NodeMCU-Based Smart System for Monitoring Total Dissolved Solids in Diverse Water Sources

Abstract

Continuous monitoring of water quality is essential for protecting public health and ensuring environmental sustainability. This study presents the design and preliminary assessment of a low-cost Internet of Things (IoT)-based monitoring prototype developed to measure Total Dissolved Solids (TDS) using a NodeMCU (ESP8266) microcontroller integrated with an analog conductivity-based sensor. The proposed system is designed as a portable and scalable architecture capable of real-time data acquisition and on-site visualization.The prototype was tested using three representative water samples distilled water, municipal tap water, and river water to evaluate its functional capability to distinguish between varying dissolved solid concentrations. The measured TDS values demonstrated clear differentiation between low and moderate mineral content levels, indicating consistent sensor response behavior. The findings suggest that the system is suitable for preliminary water quality screening applications, particularly in resource-limited or decentralized monitoring environments.Although the prototype shows promising functional performance, comprehensive statistical validation and calibration against laboratory-grade instrumentation are required to quantify measurement accuracy and long-term stability. Future work will focus on repeatability analysis, temperature compensation integration, and extended field testing to enhance metrological reliability.