main.cpp

#include <Arduino.h>
#include "DHT.h"
#include <iostream>
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <PubSubClient.h>
#include "mqttcert.h"

WiFiClientSecure espClient;
PubSubClient mqttClient(espClient);

//DHT setup

#define DHTPIN 4 // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // DHT 11
DHT dht(DHTPIN, DHTTYPE);


void mqttConnect()
{
  while (!mqttClient.connected())
  {

    Serial.print("In mqttConnect(), connecting...  ");

    if (mqttClient.connect(MQTT_CLIENT_ID, MQTT_USERNAME.c_str(), MQTT_PASSWORD))
    {
      Serial.println("...connected to mqtt server!");
      Serial.print("Subscribing to topic:  ");
      Serial.println(MQTT_TOPIC_NAME.c_str());

      // Subscribe topic with default QoS 0
      // Let's just subscribe to the same feed we are publishing to, to see if our message gets recorded.
      mqttClient.subscribe(MQTT_TOPIC_NAME.c_str());
    }
    else
    {
      Serial.println("...mqttConnect() failed, status code =");
      Serial.println(mqttClient.state());
      Serial.println("try again in 5 seconds...");
      delay(5000); // Wait 5 seconds before retrying
    }
  }
}


void setup()
{
Serial.begin(9600);
  Serial.println();
  Serial.println("Hello MQTT program");
  Serial.print("Attempting to connect to WiFi SSID:  ");
  Serial.println(WIFI_SSID);
  Serial.print("Connecting");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);

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

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.print("IP address:  ");
  Serial.println(WiFi.localIP());
  Serial.println("Setting up MQTT...");

  espClient.setCACert(CA_CERT);
  mqttClient.setServer(MQTT_SERVER, 8883);

  dht.begin();
}

void loop()
{
  
  delay(2000);

  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  if (isnan(h) || isnan(t) || isnan(f))
  {
    Serial.println(F("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);

  mqttConnect();

  // String dataToSend = String(millis()); // dataToSend could be a sensor reading instead
    String dataToSend = String(h, t);

    Serial.print("Publishing data:  ");
    Serial.print(F("Humidity: "));
    Serial.print(h);
    Serial.print(F("%  Temperature: "));
    Serial.print(t);
    Serial.print(F("°C "));
    Serial.print(f);
    Serial.print(F("°C "));
    Serial.println(F("°F"));
    Serial.println(dataToSend);
    
    mqttClient.publish(MQTT_TOPIC_NAME.c_str(), dataToSend.c_str());

}