WOKWI ESP32 + MQTT GO Broker

WOKWI ESP32 + MQTT GO Broker

// Create an MQTT Connection

// TCP Connection

// import the WiFi and PubSubClient libraries

//The WiFi library allows ESP32 to establish connections with Wi-Fi networks

//The PubSubClient library enables ESP32 to connect to an MQTT broker for publishing messages and subscribing to topics.

#include <WiFi.h>

#include "PubSubClient.h"

// WiFi

char ssid[]="Wokwi-GUEST";

char pass[]="";

// MQTT Broker

const char *mqtt_broker = "broker.MQTTGO.io";//"broker.emqx.io";//Public Broker

const char *mqtt_username = "mqttgo";

const char *mqtt_password = "public";

const int mqtt_port = 1883;

const char *topic_subsrcibe = "mqttgo/esp32/power";//Topic ESp32 Subs

const char *topic_publish="mqttgo/esp32/hi";

WiFiClient hamada;//WIFI Opject

PubSubClient client(hamada);//OOP

//int y ;

//void function(int x);

//call_function(y);

void callback(char *topic, byte *payload, unsigned int length);

#define LED 2

bool ledState=false;

void setup(){

   // Setting LED pin as output

    pinMode(LED, OUTPUT);

    digitalWrite(LED, LOW);  // Turn off the LED initially

    //Open a serial connection to display program results and establish a connection to the Wi-Fi network.

    // Set software serial baud to 115200;

    Serial.begin(115200);

    // Connecting to a Wi-Fi network

    WiFi.begin(ssid, pass);

    while (WiFi.status() != WL_CONNECTED) {

        delay(500);

        Serial.println("Connecting to WiFi..");

    }

        Serial.println("Connected to the Wi-Fi network");

    // Utilize PubSubClient to establish a connection with the MQTT broker.

    //connecting to a mqtt broker

    Serial.println("Before Connect MQTT");

    //Broker Configuration

    client.setServer(mqtt_broker, mqtt_port);

   

   while (!client.connected()) {

        String client_id = "esp32-client-";

        client_id =client_id+ String(WiFi.macAddress());

        //consloe.log("x"+"y");//xy

        //ESP32-ID -----> esp32-client-macaddress

        //variable.c_str()--->char [] , String

        Serial.printf("The client %s connects to the public MQTT broker\n", client_id.c_str());

        if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {

            Serial.println("Public MQTT broker connected");

        } else {

            Serial.print("failed with state ");

            Serial.print(client.state());//1 , 2 , 5

            delay(2000);

        }

    }

    Serial.println("After Connect MQTT");

    client.publish(topic_publish, "Hi, I'm ESP32 ^^");

    client.subscribe(topic_subsrcibe);

    client.setCallback(callback);

}

void loop() {

    client.loop();

}

void callback(char* topic, byte* message, unsigned int length) {

  printPayload(topic, message, length);  

}

void printPayload(char* topic, byte* message, unsigned int length) {

  // Printing Received Message

  Serial.print("Message received on topic: ");

  Serial.println(topic);

  String messageTemp;

  for(int i=0; i<length; i+=1) {

    messageTemp += (char)message[i];

  }

  if(String(topic) == "mqttgo/esp32/power"){

      Serial.println("OK");

      if(messageTemp=="ON"){

        Serial.println("Led ON");

        digitalWrite(2,HIGH);

      }  

      if(messageTemp=="OFF"){

        Serial.println("Led OFF");

        digitalWrite(2,LOW);

      }

  }

  Serial.println(messageTemp);

}