ESP32 MQTT Publish and Subscribe

ESP32 MQTT Publish and Subscribe RFID ID No, LED on/off/flash

參考來源 https://randomnerdtutorials.com/esp32-mqtt-publish-subscribe-arduino-ide/

/*********
  Rui Santos
  Complete project details at https://randomnerdtutorials.com 
*********/

#include <WiFi.h>
#include <PubSubClient.h>
#include <SPI.h>
#include "MFRC522.h"

const int RST_PIN = 22; // Reset pin
const int SS_PIN = 21; // Slave select pin
//==========================
//esp32     mfrc522
//21        SDA
//18        SCK
//23        MOSI
//21        MISO
//22        RST
//GND       GND
//3.3v      3.3V
//==========================

// Update these with values suitable for your network.
//const char *ssid = "PTS-2F";
//const char *pass = "";
//const char *ssid = "WBR-2200";
//const char *pass = "0226452362";

const char *ssid = "74170287";
const char *pass = "24063173";
//const char *ssid =  "yourSSID";     // change according to your Network - cannot be longer than 32 characters!
//const char *pass =  "yourPASSWORD"; // change according to your Network


#define MQTTid              ""                           //id of this mqtt client
#define MQTTip              "broker.mqtt-dashboard.com"  //ip address or hostname of the mqtt broker
#define MQTTport            1883                         //port of the mqtt broker
#define MQTTuser            "alex9ufo"                   //username of this mqtt client
#define MQTTpsw             "alex1234"                   //password of this mqtt client
//#define MQTTuser          "your_username"              //username of this mqtt client
//#define MQTTpsw           "your_password"              //password of this mqtt client
#define MQTTpubQos          2                            //qos of publish (see README)
#define MQTTsubQos          1                            //qos of subscribe

MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance

//Variables
long lastMsg = 0;
char jsonChar[100];
String IDNo_buf="";
const int BUILTIN_LED = 2; //D2
bool Flash = false;  //true
//=============================================================================
boolean pendingDisconnect = false;
void mqttConnectedCb(); // on connect callback
void mqttDisconnectedCb(); // on disconnect callback
void mqttDataCb(char* topic, byte* payload, unsigned int length); // on new message callback

WiFiClient wclient;
PubSubClient client(MQTTip, MQTTport, mqttDataCb, wclient);

//=============================================================================
String printHex(byte *buffer, byte bufferSize) {
      String id = "";
      for (byte i = 0; i < bufferSize; i++) {
        id += buffer[i] < 0x10 ? "0" : "";
        id += String(buffer[i], HEX);
      }
      return id;
    }
//=============================================================================
void mqttConnectedCb() {
  Serial.println("connected");
 
  // Once connected, publish an announcement...
  client.publish("alex9ufo/outTopic/RFID/json", jsonChar, MQTTpubQos, true); // true means retain
  // ... and resubscribe
  client.subscribe("alex9ufo/inTopic", MQTTsubQos);

}
//=============================================================================
void mqttDisconnectedCb() {
  Serial.println("disconnected");
}
//=============================================================================
void mqttDataCb(char* topic, byte* payload, unsigned int length) {

  /*
  you can convert payload to a C string appending a null terminator to it;
  this is possible when the message (including protocol overhead) doesn't
  exceeds the MQTT_MAX_PACKET_SIZE defined in the library header.
  you can consider safe to do so when the length of topic plus the length of
  message doesn't exceeds 115 characters
  */
  char* message = (char *) payload;
  message[length] = 0;

  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  Serial.println(message);
  // Switch on the LED if an 1 was received as first character
  if (message[0] == '0') {
     digitalWrite(BUILTIN_LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
     // but actually the LED is on; this is because
     Serial.println("Received 0 , Send LOW TO BuildIn_LED");
    }
   if (message[0] == '1') {
     digitalWrite(BUILTIN_LED, HIGH);   // Turn the LED off (Note that HIGH is the voltage level
     // but actually the LED is on; this is because
     Serial.println("Received 1 , Send HIGH TO BuildIn_LED");
   }
    if (message[0] == '2') {
     digitalWrite(BUILTIN_LED, HIGH);   // Turn the LED off (Note that HIGH is the voltage level
     // but actually the LED is on; this is because
     Serial.println("Received 2 , Flashing BuildIn_LED ");
     Flash = true;
   } //if (message[0] == '2')
}
//======================================================
void setup_wifi() {
  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, pass);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
 
}
//======================================================
void setup() {
  Serial.begin(115200);
  setup_wifi();
  pinMode(BUILTIN_LED, OUTPUT);
  Serial.println(F("Booting...."));
  SPI.begin();           // Init SPI bus
  mfrc522.PCD_Init();    // Init MFRC522
  Serial.println(F("Ready!"));
  Serial.println(F("======================================================"));
  Serial.println(F("Scan for Card and print UID:"));
}
//======================================================
void process_mqtt() {
  if (WiFi.status() == WL_CONNECTED) {
    if (client.connected()) {
      client.loop();
    } else {
    // client id, client username, client password, last will topic, last will qos, last will retain, last will message
      if (client.connect(MQTTid, MQTTuser, MQTTpsw, MQTTid "/status", 2, true, "0")) {
          pendingDisconnect = false;
          mqttConnectedCb();
      }
    }
  } else {
    if (client.connected())
      client.disconnect();
  }
  if (!client.connected() && !pendingDisconnect) {
    pendingDisconnect = true;
    mqttDisconnectedCb();
  }
}
//======================================================
void loop() {
  process_mqtt();
  long now = millis();
  if (Flash)
  {
    digitalWrite(BUILTIN_LED, !digitalRead(BUILTIN_LED));
    delay(500);
  }

 
  if (mfrc522.PICC_IsNewCardPresent() && mfrc522.PICC_ReadCardSerial()) { // 如果出現新卡片就讀取卡片資料
     delay(100);
     String IDNo = printHex(mfrc522.uid.uidByte, mfrc522.uid.size);
     // Show some details of the PICC (that is: the tag/card)
     if ((IDNo != IDNo_buf) || (now - lastMsg > 5000)) {  //不同卡片 或是 等5秒
         lastMsg = now;
         Serial.print(F("Card UID:"));
         Serial.println(IDNo);
         //Serial.println(IDNo_buf);
   
         IDNo_buf="";
         IDNo_buf=IDNo;
         // Convert data to JSON string
         String json =
         "{\"data\":{"
         "\"RFID_No\": \"" + IDNo + "\"}"
         "}";
         // Convert JSON string to character array
         json.toCharArray(jsonChar, json.length()+1);
   
         if  (client.connected()) {
              Serial.print("Publish message: ");
              Serial.println(json);
              // Publish JSON character array to MQTT topic
             client.publish("alex9ufo/outTopic/RFID/json",jsonChar);
         }
      } // if ((IDNo != IDNo_buf) || (now - lastMsg > 5000))
  }  // if (mfrc522.PICC_IsNewCardPresent()

}   //Loop
//======================================================