Design of an ESP32-based Intelligent Door Lock Control System

Abstract

Conventional commercial smart door locks generally adopt only a single unlocking mode and rely heavily on Wireless Fidelity (Wi-Fi) for alarm transmission, which results in poor accessibility for the elderly and children and inadequate local security protection. Once the wireless connection is disrupted, remote alarm and monitoring functions become unavailable, bringing potential risks to household security. To address these drawbacks, this paper proposes a multimodal smart door lock control scheme based on the ESP32-S3 microcontroller unit (MCU). The system integrates three identity authentication methods: keypad password verification, ZW101 fingerprint recognition, and RC522 radio-frequency identification (RFID) card authentication. A SIM7600 4th Generation mobile communication technology (4G) module is deployed to realize offline short message service (SMS) alarming, while a 28BYJ-48 stepper motor driven by a ULN2003 chip performs physical locking and unlocking operations. An SSD1306 organic light-emitting diode (OLED) screen acts as the human-machine interaction terminal to display real-time system status. The whole system forms a closed-loop workflow including data acquisition, logic judgment and feedback execution. Hardware schematics and printed circuit board (PCB) layouts are designed on the Jialichuang-electronics design automation (JLC-EDA) platform, and modular firmware is developed within the Espressif Internet of Things Development Framework (ESP-IDF). Multiple encryption mechanisms are adopted for key data storage and transmission to enhance information security. Functional experiments show that the average system response time reaches approximately 1.8 s, and the fingerprint recognition accuracy exceeds 97%. When four consecutive failed authentication attempts are detected, the system triggers local alerts and sends short message service (SMS) alarm messages to designated administrators via the 4G cellular network. The stepper motor module achieves reliable positioning and stable operation. This design realizes local multimodal unlocking and network-independent security warning at low cost. It can meet the daily security requirements of households and has practical application value for residential smart home scenarios.