AL JIHAD, Naratama Galant; FATIH MUFADHDHAL, Muhammad; APRIANTO, Rizal. Design and Development of a Countdown Timer System in the Passenger Pickup and Drop-off Area Based on Ultrasonic Sensor. Jurnal Perintis: Pengembangan Riset Inovatif Teknik, Teknologi, dan Sains, Tegal, Indonesia, v. 2, n. 2(Maret-April), p. 83–91, 2026. Disponível em: https://ejournal.pktj.ac.id/index.php/perintis/article/view/117. Acesso em: 29 apr. 2026.