CAFFE VISITOR COUNTER SYSTEM USES ANDROID INTEGRATED ULTRASONIC SENSORS AND BLUETOOTH. Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics, [S. l.], v. 8, n. 1, p. 21–26, 2025. DOI: 10.15408/gpn2qc13. Disponível em: https://journal.uinjkt.ac.id/index.php/al-fiziya/article/view/41892. Acesso em: 17 jun. 2026.