Contents Introduction
According to Gartner, the gross output value of the Internet of Things (IoT) applications will reach USD 3.9-11.1 trillion in 2025, and the use of these applications will be most prevalent in the manufacturing and healthcare industries. Gartner predicts the ubiquitous use of IoT applications by 2025. IoT platforms must operate with low power consumption and be highly scalable and available in small sizes. Customized embedded platforms satisfy user needs and play crucial roles in everyday life. Owing to the flexibility, portability, and low installation costs, platforms have become increasingly prevalent. Common designs for IoT deployment involve the use of sensors or controllers to collect data, construction of autonomous industrial control systems, development of smart cities, and deployment of other types of IoT devices. Two primary goals of IoT deployment are to streamline energy usage in everyday life and to reduce human resources costs [9]. In this study, an online transmission device was designed to be installed at the entrance of a venue. The entry password and records are managed simultaneously through Internet-connected devices. This study adopted a universal asynchronous receiver-transmitter (UART) interface and a communication module for the designed device to acquire an Internet protocol (IP) address through a Wi-Fi connection and verify its connection status and communication with the backend system. The device was integrated with a cloud management system and an IoT energy management system (EMS) to assign user passwords and check device status through a cloud server. The Wi-Fi module firmware is coordinated with a real-time operating system (RTOS) to perform time-division multiplexing and switch assignments. In the RTOS, time-division multiplexing operates through a microcontroller unit (MCU) that switches between multiple assignments and allocates resources. The module firmware uses the RTOS to perform three primary threads of instructions, namely Wi-Fi connection, Wi-Fi data transmission, and UART data transmission and reception. The thread for Wi-Fi connection processes the connection with the Wi-Fi AP router to acquire an IP address for communication with the backend system. The thread for Wi-Fi data transmission focuses on initiating the web socket service and registers the relevant callbacks. The Transport Layer Security (TLS) protocol establishes a safe connection. When the manager of a venue enters identification data, the system generates and sends a PIN code. After receiving the PIN code, the venue renter can enter the corresponding numbers using the keypad of the electronic lock to enter the venue. The manager can use the backend cloud system to configure the valid period of the PIN code. This reduces the management cost and eliminates the typical requirements for extra devices or programs, thereby ensuring the convenience of the manager and renter. Currently, numerous smart locks are commercially available. However, few such products focus on the commercial remote control. Moreover, most existing products use Bluetooth transmission, require users to download the corresponding apps and entail prolonged procedures for user registration and key sharing. Consequently, these products are not appropriate for short-term renters. By contrast, the system developed in this study is suitable for the short-term lease of venues (including hotel rooms or shared office space). Therefore, an office leasing company can be a user of the proposed system to improve space management efficiency.
