Design and Development of an Intelligent Laboratory Management System Based on STM Processors

The hardware part of the system is designed using a modular expansion approach from the inside out. Initially, the core module of the minimum system design was completed using the STM32F407 development board [13]. Subsequently, the design of the peripheral expansion modules around the minimum system was gradually completed in separate modules [14]. Finally, all modules were combined into one system to achieve the corresponding functions.

In Figure 2, the overall workflow of the system is as follows: The QR code containing information about the laboratory equipment is read by the GM65 barcode scanner [15-16]. The information characteristics of the experimental instruments contained in the QR code are then read. The control program written under the Keil5 software controls the serial port of the microcontroller, enabling serial communication between the GM65 barcode scanner and the microcontroller. After scanning the GM65 barcode, the information of the QR code is transmitted to the microcontroller through serial communication, realizing the reading of the laboratory experimental instrument information by the STM32, and displaying the information of the experimental instruments on the display screen. At the same time, information synchronization with the PC end is achieved through serial communication. In addition, wireless connection with the mobile terminal can be achieved through the ESP8266 wireless module, further realizing the management function of laboratory equipment.

Figure 2.

System Flowchart

In Figure 3, there are a total of three related registers for STM32 serial communication: the USART_SR Status Register, the USART_DR Data Register, and the USART_BRR Baud Rate Register.

Figure 3.

Serial Port Register Diagram

Figure 4.

Software Design Flowchart

The process of serial port data transmission involves several key steps. First, when data needs to be sent, it is written into the Transmit Data Register (TDR). Before data transmission, the system checks whether the shift register is processing other data. If not, the newly written data is immediately transferred to the shift register for transmission. Once the data is moved to the shift register, the TXE (Transmit Data Register Empty) flag is set to 1, indicating that the data in the TDR register has been cleared and new data can be written for transmission. If the TXEIE bit in the USART_CR1 register is set to 1, an interrupt is triggered whenever the TXE flag is set. Data is shifted bit by bit to the right in the shift register and sent out through the TX pin. After the transmission is completed, this process is repeated, and the TXE flag is checked to determine if new data can be sent.

The process of serial port data reception also has several key steps. Data is first received from the RX pin and then read and shifted bit by bit into the shift register under the control of the receiver. When enough bits are received to form a complete byte, this byte is moved as a whole to the Receive Data Register (RDR). During this process, the RXNE (Receive Data Register Not Empty) flag is set to 1, indicating that there is data in the RDR that can be read. Once the RXNE flag is set, it means the data is ready to be read out from the RDR register.

Barcode scanners recognize QR codes by scanning the black and white modules on the QR code with optical sensors, converting them into digital signals, and then using decoding algorithms to transform the digital signals into recognizable information.

The specific steps include: the optical sensor inside the barcode scanner emits light, scans the black and white modules on the QR code, and converts them into electrical signals, including one-dimensional codes (such as EAN-13, CODE-39, ITF-14, etc.) and two-dimensional codes (such as QR codes, Data Matrix codes, etc.). The barcode scanner converts the scanned black and white modules into digital signals for subsequent processing. The built-in decoding algorithms of the barcode scanner decode the digital signals, transforming them into recognizable information, such as website addresses, text, links, etc. The GM65 module outputs the decoded numbers or text to external devices, such as computers, cash registers, etc., in the set output format (such as USB, serial port, Bluetooth, etc.).

The wireless module used in this design is the ESP8266, which is a very powerful WIFI module capable of communicating with a microcontroller via a serial port, thus enabling programming to control the ESP8266. With the ESP8266, you can access some APIs to obtain weather information or complete network time synchronization, and also connect to the cloud platform for development. The ESP8266 comes in various specifications such as ESP-01/01S/07/07S/12E/12F/12S, and there is also the self-developed ATK-ESP8266 by Zhengdian Atom (with modified firmware and module pins). The one used in this project is the ESP-01S, but because it uses serial port transmission, the speed is relatively slow and it is not suitable for transferring large capacity data such as images or videos. The ESP8266 supports three working modes: STA, AP, and AP+STA. The AP mode is used in this project, where the ESP8266 acts as a hotspot, providing wireless access services and data access, enabling communication with the mobile end. The ESP8266 operates based on several principles. Initially, it undergoes power-on initialization, during which it loads its firmware and sets up WIFI connections. Following this, the module can link to a WIFI network using AT commands or through programming, enabling communication with other devices or the internet. Once connected, the ESP8266 is able to transmit data with other devices through the TCP/IP protocol stack, including both sending and receiving data. As a potent WIFI module, the ESP8266 is adept at communicating with and controlling other devices, making it suitable for diverse IoT applications.

In embedded development, AT commands are not only a set of instructions used for communication with the ESP8266 module, but they are also commonly used to control various communication modules, such as ESP8266 WIFI modules,4G modules, and so on. Typically, the main chip sends AT commands to the communication module through a hardware interface (such as a serial port), and the module responds with data after receiving it. By sending different AT commands, users can configure the ESP8266 module, connect to WIFI networks, establish data connections, and thus achieve communication and control with other devices. AT commands provide a simple and effective way to interact with the ESP8266 module, facilitating user development and debugging.

The following may be the AT commands used in this experiment. By setting it to AP mode, the mobile end can access network communication through relevant applications.

In this application software design, an object-oriented design approach is used. The software design concept diagram is shown below.

The system collects information through the GM65 barcode scanner and utilizes the core board for preliminary verification. If the information fails the verification, the system will display an error on the monitor and trigger an alarm mechanism. Once the information is verified successfully, it will be transmitted to the PC end via the serial port for recording, while the ESP8266 module is used to wirelessly transmit the information to the mobile end, completing remote data monitoring. The entire process emphasizes the collaborative work between hardware modules and the logical control at the software level, ensuring the accuracy of data transmission and the stability of the system. The design of the wireless module code is as follows. ESP8266("AT\r\n"); delay(50000); ESP8266("AT+CWMODE=2\rn"); delay(50000); ESP8266("AT+RST\r\n"); delay(50000); ESP8266("AT+CWSAP=\"esp\",\"12345678\", 1,4\r\n");delay(50000); ESP8266("AT+CIPMUX=1\r\n"); delay(50000); ESP8266("AT+CIPSERVER=1,333\r\n"); delay(50000);

When designing the software for a wireless module, ensuring effective communication with the ESP8266 module is crucial. By sending AT commands such as AT and AT+RST, and receiving the module's OK response, one can verify its normal working state. Additionally, sending the AT+GMR command can retrieve the module's version information, further confirming its usability. After completing these tests, one can proceed to configure network settings, such as setting the IP address, port number, and placing the module in AT mode to achieve wireless communication with the mobile end. The AT command sending function code is as follow. void ESP8266(const char* num) { u16 i,j; i = strlen(num); for (j = 0; j < i; j++) { while (USART_GetFlagStatus(USART3, USART_FLAG_TC) == RESET); USART_SendData(USART3, (uint8_t)num[j]); } } ESP8266("AT\r\n"); ESP8266("AT+CWMODE=2\r\n"); “AT+CWMODE=2”

The ESP8266(const char* num) function plays a key role in software design, enabling control and configuration of the module by sending AT commands. This design provides a foundation for the stability and reliability of the wireless communication system, ensuring the implementation of the expected functions.

Observing the prompt messages for borrowing and returning different laboratory equipment on the mobile end, TFT-LCD screen end, and computer end after the barcode scanner scans the corresponding laboratory equipment's QR code, conclusions can be drawn accordingly.

The user interface design is guided by principles of simplicity and intuitiveness, ensuring that users can navigate the system with ease. The LCD display serves as the primary point of interaction, providing a clear and concise visual representation of the oscilloscope's status. As shown in Figure 5, the display screen and mobile application synchronize to show the same information, ensuring consistency across platforms.

Figure 5.

Normal scanning display status

When the barcode scanner successfully scans the QR code of the experimental equipment, the LCD display transitions from a neutral state to indicate a borrowed state. This change is achieved with a single scan, setting the status to "borrowed." To revert the status back to "returned," users simply need to scan the QR code again. This toggle functionality is reflected in both the LCD display and the mobile application, as depicted in Figure 5.

The interface layout prioritizes user experience. Key information, such as the oscilloscope's status, is prominently displayed, while secondary details are accessible through a straightforward menu navigation system. Interactions are minimized, with most operations requiring no more than a few clicks or scans, streamlining the process for users.

When the barcode scanner detects an irrelevant QR code, the system can trigger an alarm on the driver screen and display an error, as shown in Figure 6, the test generally meets the requirements.

Figure 6.

Display Error Message on the Screen

The following image is the error message displayed on the TFT-LCD screen when an incorrect QR code is scanned.

Through the experimental results, it can be observed that when equipment is borrowed or returned, the system correctly displays relevant information prompts on the display screen, PC end, and mobile end, ensuring the accurate conveyance and timely feedback of information. During the testing process, we paid special attention to the system's response speed and accuracy in actual operation scenarios. The results showed that the system could quickly respond to the borrowing or returning operations of the oscilloscope and display corresponding information on each port, ensuring that operators could clearly understand the status of the equipment, thereby improving operational efficiency and accuracy. In addition, when the barcode scanner scans information unrelated to laboratory equipment, the system can also provide error prompts, ensuring the accuracy of the system in identifying and handling exceptions. This error prompt function is particularly important in the laboratory management system, as it can help users quickly discover and correct erroneous operations, preventing damage or loss to laboratory equipment and data, and ensuring the normal and safe operation of the laboratory.

Through the above test results and in-depth analysis, it can be confirmed that the system performs well in various functional modules, with high stability and reliability. These test results not only verify the rationality and feasibility of the system design but also provide important references for further optimization and improvement of the system. In practical applications, these test results also provide strong support for the reliability and efficiency of the system, offering users a better user experience and service guarantee.