Frequency (125kHz vs 13.56MHz)

125kHz LF readers (RDM6300) only read simple EM4100 ID tags. 13.56MHz HF readers (RC522, PN532, PN5180) handle MIFARE, NTAG and NFC phones. Check which tags you already have before buying a reader.

Supported Standards

The MFRC522 speaks ISO 14443A only. The PN532 adds 14443B, FeliCa and NFC peer-to-peer/card emulation. The PN5180 also reads ISO 15693 (ICODE) library and industrial tags at longer range.

Interface

SPI is fastest and most common. I2C saves pins and lets you chain sensors. UART/HSU is easiest on boards with spare serial ports. USB readers like the ACR122U plug straight into a PC or Raspberry Pi.

Logic Voltage

The RC522 and PN5180 logic are 3.3V only, which is perfect for ESP32, Pico and Raspberry Pi. On a 5V Arduino Uno, use a level shifter or pick a PN532 board with on-board level shifting.

Read Range & Antenna

Expect roughly 2 to 5 cm with a card on most modules; small tags read closer. The PN5180’s stronger RF front-end reaches further. Keep metal and batteries away from the antenna coil.

The Waveshare PN532 NFC HAT puts a full PN532 NFC controller on a board that plugs straight onto a Raspberry Pi’s 40-pin header, with jumpers to choose I2C, SPI or UART. Waveshare’s wiki provides ready-to-run Python examples for the Pi plus C examples for Arduino and STM32, and the HAT can also be wired to other boards with jumper leads. It’s the cleanest way to add NFC tag reading, writing and phone interaction to a Pi-based kiosk, attendance terminal or home-automation hub.

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The PN5180 is NXP’s high-performance NFC front-end and a big step up from the PN532. Its stronger RF output and dynamic power control give noticeably better read range, and it adds ISO 15693 (ICODE SLIX) support, the vicinity tags used in libraries, laundries, industrial tracking and many toys, alongside ISO 14443A/B, FeliCa and card emulation. It communicates over SPI with extra BUSY and RST lines, and community libraries such as the PN5180-Library for Arduino and ESP32 make ISO 15693 inventory straightforward.

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The M5Stack RFID 2 Unit packs an MFRC522-compatible WS1850S chip into a tiny LEGO-compatible enclosure with a Grove (HY2.0-4P) cable. There’s no soldering and only four wires on I2C address 0x28, so it snaps onto M5Stack controllers, Seeed XIAO or any ESP32 board with a Grove port. It reads MIFARE and NTAG cards and works with MFRC522 I2C libraries and UIFlow blocks. The short read distance is deliberate, helping avoid accidental reads at a tap-to-pay style kiosk.

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The Adafruit PN532 breakout is the original, well-engineered version of the board many clones copy. You get a properly tuned large antenna, clear pin labels, and Adafruit’s excellent learning guide plus the Adafruit_PN532 Arduino library and CircuitPython driver, all maintained for years. It needs a little soldering for the headers and jumpers. Note: the Amazon listing is usually sold by third-party sellers at well above Adafruit’s own list price, so compare before you buy.

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Many existing office badges, hotel cards and cheap key fobs are 125kHz EM4100 tags, which no 13.56MHz reader can see. The RDM6300 reads them and simply streams each tag’s ID over UART at 9600 baud, so the code is just a serial read. It runs from 5V with a separate coil antenna you can mount behind a panel. We’ve already covered it in detail with Arduino and ESP32 tutorials.

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The ACS ACR122U is a finished, enclosed USB NFC reader/writer that works with Windows, macOS, Linux and Raspberry Pi through the standard PC/SC interface or libnfc. It’s the tool embedded developers keep on the bench for encoding NTAG stickers, dumping card UIDs, testing firmware against real tags and prototyping desktop enrollment stations. This bundle includes NTAG213 tags and sample cards. On Linux you may need to blacklist the pn533 kernel modules before libnfc can claim it.

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Building a door lock or attendance system?

Start with the HiLetgo PN532 V3 for full NFC and phone support, or the RC522 if you only need MIFARE cards.

Learning on a tight budget?

A multi-pack of RC522 (MFRC522) modules is the cheapest way to learn SPI and RFID. Follow our RC522 Arduino tutorial.

Using a Raspberry Pi?

The Waveshare PN532 NFC HAT plugs straight onto the 40-pin header with Python examples ready to run.

Need range or ISO 15693 tags?

The PN5180 reads further and supports ICODE vicinity tags used in libraries and industry.

Already have 125kHz badges?

Only a 125kHz reader like the RDM6300 will read EM4100 fobs and cards.

Provisioning tags from a PC?

Keep an ACS ACR122U on the bench to write NTAG stickers and test cards over USB.

What’s the difference between RFID and NFC?

NFC is a subset of 13.56MHz high-frequency RFID. Every NFC reader is an RFID reader, but not every RFID reader does NFC. A basic RFID reader like the RC522 simply reads and writes tags (ISO 14443A). A true NFC controller like the PN532 or PN5180 also supports the NFC Forum standards: reading NDEF records, talking to smartphones, peer-to-peer mode and card emulation. If you want a phone to interact with your project, you need an NFC-capable reader.

RC522 vs PN532: which should I buy?

Buy the RC522 if you only need to read MIFARE Classic cards and key fobs by UID and want the cheapest, most-tutorialized option on SPI. Buy the PN532 if you want NTAG/NDEF support, DESFire, FeliCa, phone interaction, or the flexibility of I2C and UART as well as SPI. The PN532 also tolerates 5V logic on most boards thanks to level shifting, while the RC522 is strictly 3.3V.

Can I use the RC522 with a 5V Arduino Uno?

Power it only from the Uno’s 3.3V pin, never 5V. Many people connect the SPI lines directly and it often works, but the MFRC522 isn’t specified as 5V tolerant, so for a reliable build use a logic-level shifter (or resistor dividers) on SCK, MOSI and SDA/SS. Better still, pair it with a 3.3V board like the ESP32 or Raspberry Pi Pico. See our RC522 with Raspberry Pi Pico guide.

Why is my RFID reader’s range so short?

Passive tags are powered entirely by the reader’s magnetic field, so range is limited by antenna size and RF power. Typical hobby modules read cards at 2 to 5 cm and small stickers or fobs at 1 to 2 cm. Range drops sharply near metal, batteries and ground planes, and poorly tuned clone antennas make it worse. For more distance, use a larger card-sized tag, keep the antenna clear of metal, or step up to a PN5180.

Is MIFARE Classic secure enough for a door lock?

Not for anything important. MIFARE Classic’s Crypto-1 cipher has been broken for years, and many projects only check the tag’s UID, which can be cloned onto “magic” cards. For hobby projects that’s fine, but for real access control use cards with modern cryptography such as MIFARE DESFire EV2/EV3 or NTAG 424 DNA, read with a PN532 or PN5180, and verify authentication rather than just the UID.