The ability of soil to hold water, a crucial factor affecting plant growth and soil stability, is greatly influenced by the composition and structure of the soil. The employment of fly ash, a waste product from coal burning processes, as a soil additive has drawn interest due to its potential to alter soil characteristics. The present study investigates the water retention properties of fly ash when incorporated into various soil types. Specifically, the research examines sandy, loamy, and clayey soils, with fly ash content ranging from 0 to 30% for each soil type. The primary objective is to evaluate the efficacy of fly ash in enhancing soil moisture retention. A key milestone in this work is the development of an Arduino-based device capable of measuring soil moisture, temperature, and matric suction. Preliminary experiments have demonstrated the device's ability to consistently collect reliable data. Furthermore, an HX710B Air Pressure Sensor has been acquired to develop a tensiometer for measuring suction pressure, which will be integrated into the existing device. The Van Genuchten model was employed to characterize the soil water retention curve, yielding a predictive association between soil matric suction and volumetric water content. This study contributes to the sustainable management of fly ash, with potential implications for soil enhancement and water preservation.