WOKWI Active Buzzer & MQTT

WOKWI Active Buzzer & MQTT

#include <WiFi.h>

#include <PubSubClient.h>

// Define NodeMCU D2 pin  connect to Piezo Buzzer

#define BUZZER_PIN  2

// Update these with values suitable for your network.

const char* ssid =  "Wokwi-GUEST";   // your network SSID (name)

const char* password = "";   // your network password

//const char* mqtt_server = "broker.mqttdashboard.com";// choose your mqtt server

const char* mqtt_server = "broker.mqttgo.io";

WiFiClient espClient;

PubSubClient client(espClient);

long lastMsg = 0;

char msg[50];

int value = 0;

//=========================================================

void setup_wifi() {

   delay(100);

  // We start by connecting to a WiFi network

    Serial.print("Connecting to ");

    Serial.println(ssid);

    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED)

    {

      delay(500);

      Serial.print(".");

    }

  randomSeed(micros());

  Serial.println("");

  Serial.println("WiFi connected");

  Serial.println("IP address: ");

  Serial.println(WiFi.localIP());

}

//=========================================================

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

{

  Serial.print("Command from MQTT broker is : [");

  Serial.print(topic);

  int p =(char)payload[0]-'0';

  // if MQTT comes a 0 turn off LED on D2

  if(p==0)

  {

    digitalWrite(BUZZER_PIN, HIGH);

    Serial.println(" Turn Off BUZZER! ");

  }

  // if MQTT comes a 1, turn on BUZZER on pin D2

  if(p==1)

  {

    digitalWrite(BUZZER_PIN, LOW);

    Serial.println(" Turn On BUZZER! ");

  }

  Serial.println();

} //end callback

//=========================================================

void reconnect() {

  // Loop until we're reconnected

  while (!client.connected())

  {

    Serial.print("Attempting MQTT connection...");

    // Create a random client ID

    String clientId = "ESP32Client-";

    clientId += String(random(0xffff), HEX);

    // Attempt to connect

    //if you MQTT broker has clientID,username and password

    //please change following line to    if (client.connect(clientId,userName,passWord))

    if (client.connect(clientId.c_str()))

    {

      Serial.println("connected");

     //once connected to MQTT broker, subscribe command if any

      client.subscribe("alex9ufo/Command");

    } else {

      Serial.print("failed, rc=");

      Serial.print(client.state());

      Serial.println(" try again in 5 seconds");

      // Wait 6 seconds before retrying

      delay(6000);

    }

  }

} //end reconnect()

//=========================================================

void setup() {

  Serial.begin(115200);

  setup_wifi();

  client.setServer(mqtt_server, 1883);

 

  pinMode(BUZZER_PIN, OUTPUT);

  digitalWrite(BUZZER_PIN,HIGH);

}

//=========================================================

void loop() {

  if (!client.connected()) {

    reconnect();

  }

  client.setCallback(callback);

  client.loop();

}

//=========================================================