Optimization of the Automatic Bell System of STMIK Kaputama with Time Control Based on Smartphone Using Nodemcu

This research aims to design and implement an Internet of Things (IoT)-based automatic bell system integrated with a smartphone using the ESP32 microcontroller. The background of this study is the limitation of the previous automatic bell system at STMIK Kaputama, which had unclear sound quality and lacked flexibility in scheduling. The developed system utilizes the RTC DS3231 for time management, the DFPlayer Mini for audio playback, and the Blynk application as a remote control interface. The research method includes hardware design, software development, and system functionality testing The results show that the system operates according to the class schedule with clearer sound output, can be controlled via a smartphone, and supports the concept of an efficient and modem smart campus. Therefore, this system can be an effective solution to optimize the time management of academic activities on campus.