Introduction

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

Circuit Connections

MFRC522 ESP32-S3-BOX-3

SDA GPIO10

SCK GPIO12

MOSI GPIO11

MISO GPIO13

RST GPIO9

VCC 3.3v

GND GND

How It Works

When 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.

Programming

The 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.

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