HydroGuard: A Dry-Run-Protected Dual-Tank Smart Water Pump Controller for Homes using ESP8266 and Blynk IoT

Abstract:-Overflow of overhead tanks and dry running of pumps are common problems in homes where water is pumped from a sump to a roof tank by hand-operated switches. This paper presents HydroGuard, a smart home water pump controller that measures the water level in both the overhead tank and the sump with ultrasonic sensors and switches the pump through a relay and contactor driven by an ESP8266 NodeMCU. The control logic runs locally with a hysteresis band (start at 25% and stop at 95% tank level), dry-run protection (sump minimum 15%), a 30-minute maximum run timer and fail-safe handling of sensor faults, so that the pump remains protected even when Wi-Fi is unavailable. A Blynk smartphone application provides live levels, notifications, manual override and threshold settings. In calibration tests the level measurement had a mean absolute error of 0.89 cm (RMSE 0.91 cm, maximum 1.2 cm) over 10 cm to 80 cm. In a one-month field comparison with manual operation, overflow events fell from nine to zero, dry-run events from six to zero, and manual checks from about 30 to four, saving an estimated 800 litres of water per month. The prototype costs about INR 1,800.

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