Hardware Design
This system integrates several key components, including a fingerprint module, a MicroSD card reader/writer module, a PCF8563 real-time clock module, a buzzer module, a matrix keypad, an LCD1602 display, and the STC90C516RD+ microcontroller. These modules work together to create a reliable and efficient fingerprint-based attendance system.
System Block Diagram
1) Fingerprint Module
The FPM10A optical fingerprint module is used in this system. It is a well-established and widely used module known for its stability and versatility. The FPM10A can be connected via TTL serial port or USB interface and is compatible with 51-series microcontrollers, making it a suitable choice for this project.
2) Storage Module
Two options were considered for data storage:
- **Option 1: EEPROM Module**
This option uses I²C communication, which is simple to implement. However, it has limited storage capacity and a short lifespan, making it unsuitable for long-term use in this application. Therefore, it was discarded.
- **Option 2: MicroSD Card Reader Module**
This module communicates using the SPI protocol, which offers larger storage capacity and better reliability compared to EEPROM. Although it was a new protocol for the team, it was chosen due to its widespread use and scalability. Thus, the MicroSD card reader was selected as the main storage solution.
3) Real-Time Clock Module
The PCF8563 module was selected for timekeeping. Compared to the DS1302, it provides more accurate timekeeping, lower power consumption, and greater stability, making it ideal for this system.
Programming and Design Ideas
Program Flow Chart
The system supports multiple functions such as checking in, adding fingerprints, deleting individual fingerprints, searching for fingerprints, and clearing all data. Once a user is authenticated, the system records the timestamp on the MicroSD card and triggers the buzzer to indicate successful check-in.
For function selection, a 4-button matrix keypad is used, allowing users to navigate through the menu by pressing the buttons in a loop. To add a new fingerprint, the system captures two images of the same finger, stores them in buffers, and then generates a feature template. This template is saved under a specific ID, and the corresponding sector on the MicroSD card is updated.
To delete a fingerprint or search for one, the system allows users to either input an ID manually or search for a match using the fingerprint sensor. A flag bit is used to track whether an ID is active or not, ensuring consistency between the MicroSD card and the fingerprint module. When a valid ID is found, the system displays the associated check-in time.
Finally, the clear function resets both the fingerprint module and the corresponding MicroSD sectors, effectively removing all stored data. This comprehensive design ensures a secure, user-friendly, and reliable fingerprint-based attendance system.
Automotive Electronics Packaging
Packages For Automotive Electronics,Integrated Drive Electronics,Automotive Seat Heaters,Automotive Electronic Packaging
Shaanxi Xinlong Metal Electro-mechanical Co., Ltd. , https://www.cnxlalloys.com
