Instrumentation and Control System of Voice-Controlled Smart Vending Robot Using Ultrasonic Sensor, DC Motor, and MicrocontrollerUsep Suhud, Deosa Putra Caniago, Doni Sugianto Sihotang, Muhammad Khairul Amal, Muaz Azinuddin and Puan Lailatul Faizah Abu HassanEPJ Web Conf., 377 (2026) 06017DOI: https://doi.org/10.1051/epjconf/202637706017