How to Interface MFRC522 RFID Reader with the ESP32-S3-BOX

A developer demonstrates how to interface an MFRC522 RFID reader with the ESP32-S3-BOX-3 using SPI communication without interfering with the onboard display. The project uses the LovyanGFX and MFRC522v2 libraries to read RFID card UIDs and display them on the touchscreen. A custom enclosure was designed and manufactured via JUSTWAY's 3D printing service to create a professional prototype.

The ESP32-S3-BOX-3 is one of the most feature-packed ESP32 development boards available today. It combines a high-resolution capacitive touchscreen, Wi-Fi, Bluetooth, audio support, and a powerful dual-core ESP32-S3 processor into a single compact development platform. While many examples demonstrate its display or AI capabilities, there are very few projects showing how to integrate external SPI peripherals like the MFRC522 RFID reader alongside the built-in display. Since both the display and the RFID reader rely on SPI communication, many beginners assume they cannot be used together. In reality, with proper SPI initialization and chip-select handling, both devices can work seamlessly on the same ESP32-S3. In this project, we'll build a simple RFID scanner that reads the UID of any RFID card and displays it instantly on the ESP32-S3-BOX-3 touchscreen using the LovyanGFX graphics library. Why This Project?The ESP32-S3-BOX-3 is rapidly becoming one of the most popular development boards for embedded GUI applications. However, one challenge that many developers face is integrating additional SPI peripherals without interfering with the onboard display. This project demonstrates a clean and reliable method to connect an MFRC522 RFID reader while continuing to use the BOX-3 display normally. The same approach can later be expanded into projects such as: - RFID Attendance System - Smart Door Lock - NFC Login Terminal - library Management - Smart Inventory Tracking - Industrial Access Control MFRC522 ESP32-S3-BOX-3 SDA GPIO10 SCK GPIO12 MOSI GPIO11 MISO GPIO13 RST GPIO9 VCC 3.3v GND GND How It WorksWhen an RFID card is placed near the MFRC522 module, the reader captures the card's unique identifier UID . The ESP32-S3 reads this UID over SPI and immediately displays it on the touchscreen while simultaneously printing it to the Serial Monitor. Although both the display and RFID reader use SPI communication, they coexist without conflict because each device uses its own chip-select line. This makes it possible to build much larger touchscreen applications while continuing to use external SPI peripherals. ProgrammingThe project is written using the Arduino IDE The following libraries are used: - LovyanGFX - MFRC522v2 - SPI LovyanGFX handles the onboard display while the MFRC522v2 library communicates with the RFID reader. After initializing both devices, the program continuously waits for a new RFID card. Whenever a card is detected, its UID is converted into a hexadecimal string and displayed on the screen. Designing a Professional Enclosure With JUSTWAYAlthough the RFID scanner works perfectly on a breadboard, If you wanted the final prototype to look more like a finished product than a development setup. A custom enclosure not only protects the electronics but also improves portability, cable management, and the overall presentation of the project during demonstrations. To build the enclosure, I designed the parts in CAD and had them manufactured through JUSTWAY . Instead of manually fabricating the enclosure, using a professional manufacturing service resulted in a much cleaner finish and ensured that the ESP32-S3-BOX-3, RFID module, and wiring all fit together accurately. One feature I particularly appreciate is the instant online quotation system . After uploading the CAD files, the platform automatically generates pricing and allows you to customize materials, colors, surface finishes, and manufacturing processes without waiting for manual quotations. Another useful feature is their free Design for Manufacturability DFM review , which helps identify issues such as thin walls, unsupported features, or tolerance problems before production begins. Catching these issues early can save both time and material, especially when working on functional prototypes. For this project, 3D printing was the ideal manufacturing method because it allowed me to quickly produce a durable enclosure while preserving the fine details of the design. However, if the project evolves beyond a prototype, JUSTWAY https://www.justway.com/ also offers several manufacturing options that make scaling much easier. 3D Printing – Rapid prototyping using multiple materials including PLA, ABS, Resin, Nylon, PETG, and engineering plastics. CNC Machining – Precision machining for aluminum, brass, stainless steel, copper, plastics, and other engineering materials. Sheet Metal Fabrication – Laser cutting, bending, welding, and finishing for custom enclosures and brackets. Injection Molding – Suitable for large-scale manufacturing with consistent quality and excellent repeatability. Urethane Vacuum Casting – Ideal for producing small batches of production-quality parts before investing in injection molds. PCB Manufacturing – Multi-layer PCB fabrication with various finishes, solder mask options, and quality inspection. PCB Assembly PCBA – Complete SMT and through-hole assembly services, making it possible to receive fully assembled circuit boards. Rapid Prototyping Services – Fast iteration cycles with engineering support to refine designs before mass production. One aspect that makes the platform especially convenient is that all these services are available through a single workflow. As a project grows from a simple prototype into a production-ready product, there is no need to switch between different manufacturing vendors. Whether you're building a one-off hobby project, preparing a prototype for a competition, or planning to manufacture a product in larger quantities, having access to multiple fabrication technologies under one platform significantly simplifies the development process while maintaining professional quality. ResultsThe RFID scanner successfully detects multiple RFID cards and displays their unique identifiers instantly on the ESP32-S3-BOX-3 display with virtually no noticeable delay. At the same time, the UID is printed to the Serial Monitor, making debugging and integration with larger projects much easier. This simple project serves as a solid foundation for more advanced embedded systems involving authentication, attendance, inventory management, and IoT. Future ImprovementThis project can easily be extended with: - Wi-Fi Database Logging - Google Sheets Integration - MQTT Support - Touchscreen Menus - User Databse - Access Control - NFC Authentication - Cloud Dashboard - Thermal Printer Support Interfacing an MFRC522 RFID reader with the ESP32-S3-BOX-3 is much simpler than it first appears. By properly configuring the SPI interface and using LovyanGFX for the onboard display, both peripherals can operate simultaneously without conflict. Although this project is intentionally minimal, it provides a reliable starting point for anyone looking to build more sophisticated RFID-enabled embedded systems using the ESP32-S3 platform. Read more javascript:void 0