Rubiyatno and Putra Sastaman 2026. Development and Preliminary Evaluation of an IoT Enabled Ultrasonic System for Volleyball Jump Measurement. Musamus Journal of Physical Education and Sport (MJPES). 8, 4 (Oct. 2026), 1508-1517. DOI:https://doi.org/10.35724/mjpes.v8i4.8119.