Arduino + RFID 读取 IC 卡 Arduino uno中获得RFID的UID 并通过串口转发RFID卡号

RFID简介：射频识别即RFID（Radio Frequency IDentification）技术，又称无线射频识别，是一种通信技术，可通过无线电讯号识别特定目标并读写相关数据，而无需识别系统与特定目标之间建立机械或光学接触。常用的有低频（125k~134.2K）、高频（13.56Mhz）、超高频，微波等技术。RFID读写器也分移动式的和固定式的，目前RFID技术应用很广，如：图书馆，门禁系统，食品安全溯源等。

硬件准备

（基于Arduino的开发板、MFRC522读卡器模块）
Arduino Uno * 1

RFID-RC522 模块 * 1

IC卡 * 1-2

RFID技术现在都非常成熟和应用广泛，今天我们就来看看这个RFID如何实现读取里面的数据

接线

Arduino Uno <—> RFID-RC522
10 <—> SDA
13 <—> SCK
11 <—> MOSI
12 <—> MISO
null <—> IRQ
GND <—> GND
9 <—> RST
3.3V <—> 3.3V

需要用到RFID-RC522的库

法一、下载：https://github.com/miguelbalboa/rfid
下载解压到Arduino IDE的安装路径里的库文件夹libraries
https://download.csdn.net/download/v86337286/11813061

法二、点开管理库，在搜索栏里输入RC522，找到图中的库，

点击安装（我这图是已经安装过）

示例代码 .

Arduino + RFID 读取 IC 卡信息

读取 IC 卡信息后并通过串口将卡号及0扇区卡号数据打印出来，其他15个扇区不显示扇区内容
代码如下

/** --------------------------------------------------------------------------------------------------------------------* Example sketch/program showing how to read data from a PICC to serial.* --------------------------------------------------------------------------------------------------------------------* This is a MFRC522 library example; for further details and other examples see: https://github.com/miguelbalboa/rfid* * Example sketch/program showing how to read data from a PICC (that is: a RFID Tag or Card) using a MFRC522 based RFID* Reader on the Arduino SPI interface.* * When the Arduino and the MFRC522 module are connected (see the pin layout below), load this sketch into Arduino IDE* then verify/compile and upload it. To see the output: use Tools, Serial Monitor of the IDE (hit Ctrl+Shft+M). When* you present a PICC (that is: a RFID Tag or Card) at reading distance of the MFRC522 Reader/PCD, the serial output* will show the ID/UID, type and any data blocks it can read. Note: you may see "Timeout in communication" messages* when removing the PICC from reading distance too early.* * If your reader supports it, this sketch/program will read all the PICCs presented (that is: multiple tag reading).* So if you stack two or more PICCs on top of each other and present them to the reader, it will first output all* details of the first and then the next PICC. Note that this may take some time as all data blocks are dumped, so* keep the PICCs at reading distance until complete.* * @license Released into the public domain.* * Typical pin layout used:* -----------------------------------------------------------------------------------------*             MFRC522      Arduino       Arduino   Arduino    Arduino          Arduino*             Reader/PCD   Uno/101       Mega      Nano v3    Leonardo/Micro   Pro Micro* Signal      Pin          Pin           Pin       Pin        Pin              Pin* -----------------------------------------------------------------------------------------* RST/Reset   RST          9             5         D9         RESET/ICSP-5     RST* SPI SS      SDA(SS)      10            53        D10        10               10* SPI MOSI    MOSI         11 / ICSP-4   51        D11        ICSP-4           16* SPI MISO    MISO         12 / ICSP-1   50        D12        ICSP-1           14* SPI SCK     SCK          13 / ICSP-3   52        D13        ICSP-3           15*/#include <SPI.h>
#include <MFRC522.h>#define RST_PIN         9          // Configurable, see typical pin layout above
#define SS_PIN          10         // Configurable, see typical pin layout aboveMFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instancevoid setup() {Serial.begin(9600);     // Initialize serial communications with the PCwhile (!Serial);        // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)SPI.begin();            // Init SPI busmfrc522.PCD_Init();     // Init MFRC522mfrc522.PCD_DumpVersionToSerial();  // Show details of PCD - MFRC522 Card Reader detailsSerial.println(F("Scan PICC to see UID, SAK, type, and data blocks..."));
}void loop() {// Look for new cardsif ( ! mfrc522.PICC_IsNewCardPresent()) {return;}// Select one of the cardsif ( ! mfrc522.PICC_ReadCardSerial()) {return;}// Dump debug info about the card; PICC_HaltA() is automatically calledmfrc522.PICC_DumpToSerial(&(mfrc522.uid));
}

运行此代码并将其中一张卡放入RFID卡时，很多信息显示在Arduino IDE的串行监视器上

看完了上面那如何在Arduino中获得RFID的UID？

Arduino uno中只获得RFID的UID 并通过串口转发

法一

创建了另一个函数： PICC_DumpDetailsToSerialUid(Uid *uid)函数如下

//This is just for read UID!
void MFRC522::PICC_DumpDetailsToSerialUid(Uid *uid){
Serial.print(F(“Card JUST UID :”));
for (byte i = 0; i < uid->size; i++) {
if(uid->uidByte[i] < 0x10)
Serial.print(F(" 0"));
else
Serial.print(F(" "));
Serial.print(uid->uidByte[i], HEX);
}
Serial.println();
}

可以把它放在你需要的任何地方
示例：

添加该功能后，您需要进入第410行的 MFRC522.h 库并添加

void PICC_DumpDetailsToSerialUid(Uid *uid);

在该库中进行了这两次编辑后，您可以在任意位置调用该函数 .
示例：

用Arduino调用它： mfrc522.PICC_DumpDetailsToSerialUid(&(mfrc522.uid)); 只仅且只有一个函数用于uid读取
效果

法二

返回UID的函数 .

/*** mfrc522.PICC_IsNewCardPresent() should be checked before * @return the card UID*/
unsigned long getID(){if ( ! mfrc522.PICC_ReadCardSerial()) { //Since a PICC placed get Serial and continuereturn -1;}unsigned long hex_num;hex_num =  mfrc522.uid.uidByte[0] << 24;hex_num += mfrc522.uid.uidByte[1] << 16;hex_num += mfrc522.uid.uidByte[2] <<  8;hex_num += mfrc522.uid.uidByte[3];mfrc522.PICC_HaltA(); // Stop readingreturn hex_num;
}

例如这样使用：

if(mfrc522.PICC_IsNewCardPresent()) {unsigned long uid = getID();if(uid != -1){Serial.print("Card detected, UID: "); Serial.println(uid);}
}