SISTEM MONITORING LEVEL AIR DAN PENGENDALIAN POMPA OTOMATIS BERBASIS SENSOR ULTRASONIK AO2YY4W DAN ESP32

Manual filling of water tanks may cause overflow and unnecessary electricity consumption when the pump continues to operate after the tank reaches its maximum level. This study aims to develop an automatic water level monitoring and pump control system using an A02YY4W RS485 ultrasonic sensor and an ESP32. An experimental method with a prototype approach was employed. The system uses the A02YY4W ultrasonic sensor to measure water level, an LM35 to monitor water temperature, an ESP32 as the processing and control unit, an RS485 to TTL module as the communication interface, and a relay to control the water pump. System information is displayed through a local web server hosted on the ESP32. Sensor calibration was conducted at 10 water-level variations, resulting in an average absolute difference of 0.60 cm and an average error of 1.86%. Filling tests were performed from initial water levels of 0%, 25%, and 50% until reaching the maximum level of 100%. The results show that the system can track water-level changes and control the pump automatically. Fluctuations were mainly observed during filling from lower initial levels due to water surface movement, but they did not interfere with the control function. Changes in water level, temperature, and pump status were displayed through the web interface. The developed system is suitable for automatic water level monitoring and pump control in water storage systems.