M5Stack NFC Universal Unit ST25R3916

The NFC Universal Unit from M5Stack is a read and write module for 13.56 MHz based on the high-performance NFC frontend ST25R3916 from STMicroelectronics. In reader/writer mode, the module supports the standards NFC-A/B (compatible with ISO 14443A/B), NFC-F (FeliCa), and NFC-V (ISO 15693), covering a wide range of common NFC and RFID tags, cards, and transponders. Additionally, the unit supports card emulation as NFC-A or NFC-F, as well as a custom protocol mode for proprietary protocol implementations. The automatic antenna tuning and high-sensitivity receiver ensure stable reading operations up to a distance of approximately 40 mm. The module is connected via I2C with address 0x50 (100 or 400 kHz) at the Grove port, allowing direct attachment to M5Stack controllers and other development boards. A suitable Grove cable is included. The power consumption remains very low at 19.33 µA in sleep mode and rises to 67.65 mA during continuous reading. The housing features building block-compatible mounting holes for mechanical integration into custom setups. Programming is done via UiFlow2 or the Arduino IDE with the M5Unit-NFC library. This makes the unit suitable for access control, identity verification, and many other NFC applications.

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Features:

NFC frontend ST25R3916 by STMicroelectronics reads and writes tags according to NFC-A/B, NFC-F (FeliCa), and NFC-V (ISO 15693)
Card emulation as NFC-A or NFC-F allows the unit to be used as a virtual card
Automatic antenna tuning and high-sensitivity receiver ensure stable reading operations up to approximately 40 mm
I2C interface with address 0x50 at the Grove port enables direct connection to M5Stack controllers
Power consumption of only 19.33 µA in sleep mode is also suitable for battery-powered applications
Building block-compatible mounting holes facilitate mechanical integration into custom projects

Example Applications:

Access control with NFC cards, key fobs, or wristbands
Identity verification and authentication at terminals and machines
Inventory and goods tracking via NFC tags on objects
Interactive exhibition or museum projects with NFC-controlled content
Prototypes for payment and ticketing systems with card emulation

Documentation:

Technical Specifications:

Manufacturer: M5Stack
Manufacturer SKU: U216
EAN: 6972934176417
NFC Chip: ST25R3916-AQWT (STMicroelectronics)
Frequency: 13.56 MHz
Reader/Writer Protocols: NFC-A/B (ISO 14443A/B), NFC-F (FeliCa), NFC-V (ISO 15693)
Card Emulation: NFC-A, NFC-F
Operating Modes: Reader/Writer, Card Emulation, Custom Protocol
Interface: I2C, Address 0x50 (100/400 kHz), Grove Port (HY2.0-4P, PORT.A)
Read/Write Range: up to 40 mm
Supply Voltage: DC 5 V
Current Consumption: Sleep 19.33 µA, Continuous Reading 67.65 mA
Programming: UiFlow2, Arduino (M5Unit-NFC Library)
Mounting: Building block-compatible mounting holes
Certifications: CE, FCC, RoHS
Product Dimensions: 48.0 × 24.0 × 8.0 mm
Product Weight: 5.9 g
Packaging Dimensions: 140 × 90 × 8 mm
Gross Weight: 12 g