LOW COST IOT ARCHITECTURE FOR FAIL SAFE MONITORING AND CONTROL OF A SMALL SCALE HYDROPONIC SYSTEM

Abstract

Small hydroponic units require dependable nutrient circulation and timely fault reporting, but many published prototypes combine sensing and cloud dashboards without documenting fail-safe behavior, calibration, or performance metrics. This paper presents a low-cost Internet of Things architecture built around an ESP8266 controller, a reservoir-level sensor, a pH-sensing interface, an IRLZ44N pump driver, and the Blynk platform. The contribution is an edge-first control design in which pump protection remains operational when cloud connectivity is unavailable. The paper defines threshold and hysteresis logic, sensor plausibility checks, event logging, alarm priorities, and a reproducible validation protocol. A design-level analysis shows that the available prototype supports reservoir monitoring, protected pump switching, and remote status reporting; however, the current evidence does not yet establish pH-control accuracy, agronomic benefit, water saving, or long-term reliability. Accordingly, quantitative acceptance criteria are specified for calibration error, response time, packet delivery, pump duty cycle, energy use, and water balance. The architecture is appropriate for laboratory teaching and small nutrient-film or recirculating demonstrations, while publication-grade claims about crop performance require a replicated cultivation experiment. The revised design separates demonstrated functions from proposed extensions and provides a defensible path from prototype demonstration to experimentally validated smart hydroponics.