Development of Water Temperature Measuring Application Based on LoRa/LoRWAN

This paper proposes a water temperature measuring system using LoRa technology. Measuring the sea temperature is important for fishery workers because the habitat of fish and the amount of catch depend highly on the sea temperature. We examined the transmission between a sensor node and a gateway by changing the distance between them from 3 to 12 km on land. As a result of the examination, we observed some packet losses during the transmission, but it was not clear whether or not the distance caused them. As for another examination, the position of the sensor node was changed by a ship from 2.3 to 16 km, and the result showed that the distance affected the packet losses. In this study, we also designed a solar energy harvesting circuit to continuously measure the sea temperature. The sensor node floats on surface of the sea and maintains energy even if it has been cloudy for several days.