Implementation of Finite State Machine in a Goods Storage System Based on ESP8266 with Fingerprint Security Authentication on Android Devices via Application

The absence of secure storage facilities at SMK Hidayatul Ummah, Gresik, is a problem because students still use ordinary cabinets that can be accessed by anyone without key security. To overcome this, this study developed a smart locker system based on the Internet of Things (IoT) that is able to control the locker door and authenticate users through fingerprint scanning from an Android application. This system is designed using an ESP8266 microcontroller and a Finite State Machine (FSM) algorithm to set the locker status in the conditions “Available”, “Reserved”, and “Used.” User data and locker status are managed in real-time using Firebase as a cloud database. The test results show an average system response time of 1.7 seconds, which is still in the acceptable category for a real-time system. The fingerprint feature in the application also provides an additional layer of security, ensuring that only authorized users can access the locker. Visualization of locker status through color indicators-green for “Available,” yellow for “Reserved,” and red for “Used”-is considered effective in conveying information directly and intuitively. Thus, this system is able to become a safe, efficient storage solution that supports the implementation of technology in educational environments