Gravity: UART & I2C NFC Module

The Gravity: UART & I2C NFC Module is an NXP PN532-based contactless communication board designed for short-range wireless data exchange. Featuring dual I2C and UART interfaces with an onboard switch, it is ideal for makers, students, and developers building access control, identification, or device pairing projects.

NXP PN532 controller

Powered by the highly integrated NXP PN532 chip, this module supports mainstream smart cards and tags including the MIFARE Classic and NTAG series. It operates at 13.56 MHz and supports reader/writer, card emulation, and peer-to-peer communication modes.

Dual I2C and UART connectivity

An onboard toggle switch allows you to switch between I2C and UART communication over a standard Gravity PH2.0-4P connector. The module accepts 3.3V to 5.5V input voltage and works with both 3.3V and 5V controllers.

Arduino Uno I2C connection

When switched to I2C mode (address 0x48), the module connects directly to microcontrollers such as the Arduino Uno, micro:bit, or FireBeetle series. This interface simplifies wiring for embedded identification and sensor projects.

Direct PC connection via UART

In UART mode at 115200 bps, the module can connect to a PC via a standard USB-to-UART converter. This allows you to read, write, and manage compatible NFC tags using desktop PN532 software utilities.

Arduino Mega UART connection

The module can also communicate over hardware serial with development boards like the Arduino Mega 2560. This provides a robust alternative to I2C when managing multiple serial devices.

Large PCB antenna design

The board incorporates a large on-PCB antenna that provides an effective communication area and reliable tag detection. Each unit includes a Gravity 4-pin sensor wire, header pins, and an NFC tag sticker to start testing immediately.

Downloads & documentation

• Product wiki (DFRobot)