ESP8266 code to pub/sub mqtt topic (Temperature and Humidity)

ESP8266 code to pub-sub mqtt topic

#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>

// DHT settings
#define DHTTYPE DHT11
const int buttonPin = 14;
int buttonState = 0; 
const int DHTPIN = 12;
DHT dht(DHTPIN, DHTTYPE);

//Wifi Settings
const char* ssid     = "ssid";
const char* password = "wifi password";

//mqtt settings
const char* mqtt_server = "server ip";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, mqtt port);
  client.setCallback(callback);
  reconnect();
}

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, password);

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

  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("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  
  if((char)payload[0] == 'o' && (char)payload[1] == 'n') //on
    digitalWrite(4,HIGH);
  else if((char)payload[0] == 'o' && (char)payload[1] == 'f' && (char)payload[2] == 'f') //off
    digitalWrite(4,LOW);
    
  Serial.println();
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect("ESP8266Client", "username" , "password")) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("ESP8266/connection status", "Connected!");
      // ... and resubscribe
      client.subscribe("ESP8266/connection status");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void dhtMeasureNow(float &h, float &t) {
 // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" %\t");
  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.print(" *C ");
  Serial.print(f);
  Serial.print(" *F\t");
  Serial.print("Heat index: ");
  Serial.print(hic);
  Serial.print(" *C ");
  Serial.print(hif);
  Serial.println(" *F");
}

void loop() {
 
  if (!client.connected()) {
    reconnect();
  }
  //client.loop();
    delay(1000);
    float humidity, temperature;
    dhtMeasureNow(humidity, temperature);
    char sTemp[10], sHumi[10];
    dtostrf (humidity, 6, 2, sHumi);
    dtostrf (temperature, 6, 2, sTemp);
    char shadow[100];
    strcpy(shadow, "{\"state\":{\"reported\": {\"temperature\":");
    strcat(shadow, sTemp);
    strcat(shadow, ", \"humidity\":");
    strcat(shadow, sHumi);
    strcat(shadow, "}}}");
    Serial.println(shadow);
    client.publish("test", shadow);
}