High waves are sea water level that exceed normal limits and can cause danger at sea and on land, especially in coastal areas.
Purpose: Based on this, a realtime water level monitoring system was created by utilizing the IoT (Internet of Things) feature.
Methodology: The hardware used consist of the SRF04 ultrasonic sensor which serves to measure the distance of the water surface, the Arduino Pro Mini microcontroller which functions to control and to process the data readings from the ultrasonic sensor, NodeMCU ESP8266 module which functions to connect the microcontroller to the internet (data server), The DS3231 is extremely accurate real-time clock (RTC) which functions to maintain seconds, minutes, hours, day, date, month, and year information, and Micro sd card module as a storage for offline data (backup).
Results: The instrument is designed directly using a 12volt adapter that requires a 220volt AC power source and the LM2596 module which functions as a DC to DC step-down switching regulator. The instrument is applied in the Ketapang Pier, Pesawaran Regency, Lampung Province. Testing of tools and field data were carried out by comparing the distances recorded on the Blynk App and SD Card with average relative difference of 0,205%. There are two programmed water level status, that is normal and hazard.