I. Introduction
Around 70% of Earth's surface is covered by water, but water scarcity is apparent in some countries due to the shortage of water supply. Improper water management is one of the factors that contributes to this problem. Irrigation in public parks in the Philippines commonly applies scheduled irrigation wherein their sprinkler stays on for a certain duration depending on the weather. Public parks consume a huge volume of water in order to water and sustain the life of plants and other landscapes they have. Scheduled watering is the most common method used by public parks. However, estimating the amount of water leads to over or under irrigation. The farmers or the management cannot provide the required measures without the help of an expert to determine if their plants have a balanced mineral level or not [1]. Tests to determine the optimal schedule and volume of water for irrigation are done by researchers using meteorological factors, physiological characteristics of the crop which includes the crop coefficient, and the presence of fertigation [2]. Another method is the use of evapotranspiration as a reference for crop irrigation [3]. The evapotranspiration-based irrigation system setup should at least consist of a water supply, weather station, and a microcomputer or microcontroller. The data from the weather station will be used to determine the water lost. The computed value will be the amount of water that will be compensated.