The Coastal Early Warning System Based on Buoy Sensor Measurement

The Tsunami that occurred in the Sunda Strait on December 22
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2018, was a disaster that occurred in the coastal area caused by the eruption of Mount Anak Krakatau. This disaster caused hundreds of deaths and very severe damage in the western part of Java Island. This tragedy reminds us again that we are always not ready to face natural disasters that often occur in Indonesia. The Tsunami disaster cannot be predicted by devices owned by the BMKG (Meteorology and Geophysics Agency of Indonesia) because it's not the earthquake, but others caused the disaster. As we know, the disasters that often occur in coastal areas are not only Tsunami. The strength of ocean currents and large waves caused by storms are also very dangerous for people who live on the coast. Disasters can come at any time, but the understanding and readiness of safety devices are often ignored. This research designed a prototype of an early warning system of potential coastal hazards based on changes in sea waters. This system consists of 2 devices, which are devices that are placed on land as receivers and announce a warning sound of potential hazards to peoples. The second device is a buoy placed in the sea. The stainless pole is plugged into the seabed and the buoy tied with the pole using a flexible rope. The rotary encoder sensor and hall sensor mounted on the buoy to get data changes of wave heights and ocean currents. The data is transferred to the receiver on the land wirelessly using the LoRa. This system has been tested, but only in laboratories. The test results show the receiver can detect changes in current and wave parameters in real-time and monitor potential hazards properly. The potential hazard is determined by the magnitude of the wave height, strength, and current directions. However, this coastal early warning system needs to be further developed so that it can be implemented in a real disaster mitigation system in the coastal area.