<h1>RFID RC522: A Comprehensive Guide to the Popular RFID Module</h1> <p><strong>RFID RC522</strong> is one of the most ubiquitous and accessible RFID (Radio-Frequency Identification) reader/writer modules in the maker community and for prototyping. Based on the NXP MFRC522 chip, it provides a low-cost solution for reading and writing to 13.56 MHz RFID tags and cards, such as MIFARE Classic. In my personal experience, integrating the <strong>RFID RC522</strong> into an Arduino-based door access system was my first real foray into embedded security projects. It was fascinating to see how a simple card tap could trigger complex logic. I've always had a knack for understanding communication protocols, and dissecting the SPI interface of the <strong>RFID RC522</strong> felt like unlocking a new language. I firmly believe that hands-on experience with modules like this is invaluable for anyone serious about IoT development.</p> <h2>Technical Specifications and Parameters of the RFID RC522 Module</h2> <p>For any serious project, understanding the technical underpinnings is crucial. Below are the detailed specifications for the typical <strong>RFID RC522</strong> module. *Please note: These technical parameters are for reference data; specifics need to be confirmed by contacting backend management.*</p> <h3>Core Chip and Electrical Parameters</h3> <ul> <li><strong>Primary IC:</strong> NXP MFRC522 (Datasheet: MFRC52201HN1, 151 or MFRC52202HN1, 157)</li> <li><strong>Operating Frequency:</strong> 13.56 MHz</li> <li><strong>Supported Protocols:</strong> MIFARE Classic 1K, 4K, MIFARE Ultralight, MIFARE Pro, MIFARE DESFire</li> <li><strong>Communication Interfaces:</strong> SPI (Serial Peripheral Interface, up to 10 Mbps), I2C (up to 400 kHz), UART (Serial)</li> <li><strong>Supply Voltage (VDD):</strong> 2.5V to 3.3V (Absolute maximum 3.6V)</li> <li><strong>Operating Current:</strong> Typical 13-26mA during data transfer</li> </ul> <h3>Physical Dimensions and Antenna Details</h3> <ul> <li><strong>Module Dimensions:</strong> Approximately 40mm x 60mm (standard board size; variations exist).</li> <li><strong>Antenna:</strong> Integrated PCB antenna. Typical read/write distance of 10-50mm, depending on tag size and environmental factors.</li> <li><st