Water quality plays a crucial role in the growth and survival of fish. In the Mina Gawosa fish farming group in Banjarnegara, water testing is still conducted manually, making it risky to detect changes in pH and temperature in a timely manner. This study aims to develop an Internet of Things (IoT)-based system that integrates pH and temperature monitoring with automatic water replacement control in fish ponds. The system uses Wemos D1 R1 as the main controller, a pH sensor 4502C with an ADC ADS1115 16-bit module, and a DS18B20 temperature sensor. Measurement results are displayed on a 16 × 2 LCD and sent to the Blynk application for remote monitoring. When parameter values exceed the established thresholds, the system activates LED indicators, relays, and two pumps to perform water replacement. Development follows the Research and Development method using the ADDIE model. Calibration using buffer solutions of pH 6.86 and 4.01 resulted in pH reading accuracies of 95.13% and 95.31%, respectively. In a 24-hour test in the pond, the pH reading accuracy reached 94.68%, while the temperature reading accuracy reached 97.98%; both exceeded the success criteria of 90%. Black-box testing showed that sensor readings, data display and transmission, and pump activation functioned as designed. This system enables remote monitoring of water conditions and automatic activation of water replacement when pH or temperature exceeds the established thresholds.
Keywords
Blynk, DS18B20, Internet of Things, fish pond water quality, automatic monitoring and control, pH sensor 4502C, Wemos D1 R1