Introduction

Near Field Communication (NFC) is a short‑range wireless communication technology operating at 13.56 MHz. It is widely used in contactless cards, access control, mobile payments, and smart devices. An NFC reader detects and communicates with NFC tags or cards placed very close to it.

This project explains how to design and build your own NFC reader using the PN512 NFC controller. The project covers the working principle, required components, hardware connections, software logic, and applications.

For Full Project:

https://electronicsworkshops.com/how-to-make-your-own-nfc-reader-using-pn512/

Objectives of the Project

To understand the working principle of NFC technology

To interface the PN512 NFC controller with a microcontroller

To design a simple and low‑cost NFC reader system

What is PN512?

The PN512 is an NFC reader IC developed by NXP Semiconductors. It supports contactless communication at 13.56 MHz and is compatible with several RFID/NFC standards such as:

SO/IEC 14443 Type A and Type B

MIFARE Classic and Ultralight

NFC Forum Type 2 tags

Key Features of PN512

Operating frequency: 13.56 MHz

Supports SPI, I²C, and UART interfaces

Low power consumption

Integrated CRC and framing

Supports read/write operations

Block Diagram

NFC Card → PN512 NFC Reader → Microcontroller → Serial Monitor / Display

The block diagram of the NFC reader system consists of an NFC card or tag, a PN512 NFC reader module, a microcontroller, and an output unit such as a serial monitor or display. The NFC card is brought close to the PN512 antenna, where communication takes place using a 13.56 MHz electromagnetic field. The PN512 acts as the core NFC controller, handling modulation, demodulation, and data framing. It communicates with the microcontroller through SPI, I²C, or UART interface. The microcontroller processes the received data and sends the output to a display or serial monitor for user interaction.

Working Principle

The working principle of the NFC reader using PN512 is based on electromagnetic induction. When powered on, the PN512 generates a 13.56 MHz RF field through its antenna. When an NFC card or tag enters this field, it gets energized wirelessly and transmits its stored information, such as the unique identification number (UID). The PN512 receives this signal, decodes the data, and forwards it to the microcontroller. The microcontroller then processes the data and displays it on the serial monitor or uses it for further applications like access control or authentication. This communication occurs over a very short distance, ensuring secure and fast data transfer.

Circuit Diagram

This schematic shows a complete PN512-based NFC reader circuit operating at 3.3 V. The power supply section uses multiple decoupling capacitors to provide a stable and noise-free voltage to the PN512’s digital, analog, and RF supply pins. A 27.12 MHz crystal oscillator with load capacitors generates the precise clock required for NFC operation. The PN512 NFC controller is the core of the circuit, responsible for generating the 13.56 MHz RF field, handling modulation and demodulation, and managing NFC communication protocols. The RF section, consisting of inductors, capacitors, and matching resistors, forms a tuned antenna matching network that efficiently transfers energy between the PN512 and the NFC antenna. Communication with an external microcontroller is achieved through the SPI interface pins (MOSI, MISO, SCK, and NSS), while control pins such as reset and address selection configure the device operation. When powered, the PN512 energizes an NFC tag through the antenna, receives the tag’s response, processes the data internally, and sends it to the microcontroller for further use.

Manufacturing Files

Gerber

gerberDownload

Bill Of Materials

NFC(PN512)Download

Position Files

NFC(PN512)-top-posDownload

PCB files...