Grouper fish farming has good prospects. But until now, farmers still face problems related to fish theft and high fish mortality rates due to inappropriate water conditions. These two problems prompted a team of UNY students to develop a Long Range (LoRa)--based floating net cage monitoring system with grouper theft detection features. The team consists of Fitriana Dyah Ayu Rahmadhani (Electrical Engineering Education), Naufal Faiq Azhar (Electrical Engineering Education), Rifky Andigta Al Fathir (Electrical Engineering Education), Shaiful Abas (Mechatronics Engineering Education) and Nauval Hibrizi (Mechatronics Engineering Education).

"Most grouper farming entrepreneurs still use conventional monitoring methods, such as paying people to check the condition of the cages periodically at night before harvest, which can consume time, energy, and costs, so it can be concluded that this method is less effective in overcoming these problems. Therefore, we designed a LoRa-based floating net cage monitoring system called NetFarms," said Fitriana Dyah Ayu Rahmadhani, Head of the NetFarms Development Student Team.

"NetFarms is a LoRa (Long Range) based floating net cage monitoring system equipped with theft detection features using laser and Light Dependent Resistor (LDR) sensors combined with PIR (Passive Infra Red) sensors. The advantage of this design is in the application of wireless technology that allows data transmission over long distances with low power consumption," said Naufal Faiq Azhar.

NetFarms consists of three systems that synergize: the security system, the water suitability monitoring system, and the electrical system. The three systems are integrated through the ESP 32 microcontroller, where the electricity in NetFarms is supplied through off-grid solar power plants and vertical wind turbines stored in accumulators. "The security system in Netfarms uses two sensors, laser, and PIR, to detect suspicious movements near the floating net cages," said Shaiful Abbas.

If fish theft is detected, the sensor will issue two outputs that the microcontroller has managed: the first output in the form of a siren sound in the floating net cage to repel fish thieves, and the second output in the form of a notification on the smartphone of the grouper fish farming entrepreneur.

The water quality monitoring system for the suitability of grouper fish farming also uses two sensors combined to determine how suitable the environment is for grouper fish farming. The system works by checking the quality of the surrounding waters to ensure the suitability of the aquatic environment for grouper growth. Through this system, fish mortality can be minimized so as not to cause waste in the pond.(Author: Dedy, Editor: Sudaryono, Tj.lak)