Automatic College Bell Using Raspberry-Pi. International Journal of Emerging Trends in Science and Technology, [S. l.], v. 3, n. 06, p. 4086–4089, 2016. Disponível em: http://igmpublication.com/ijetst.in/index.php/ijetst/article/view/1091. Acesso em: 28 sep. 2026.