ESP32 Sensor Node Source Code

#include <ArduinoJson.h>
#include <ArduinoJson.hpp>
#include <WiFi.h>
#include <PubSubClient.h>
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include "Adafruit_BME680.h"

Adafruit_BME680 bme;

const char* ssid = "XXX";
const char* password = "XXX";
const char* mqtt_server = "XXX";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  delay(100);
  Serial.begin(115200);
  while (!Serial);

  if (!bme.begin()) {
    Serial.println("Could not find a valid BME680 sensor, check wiring!");
    while (1);
  }

  // Set up oversampling and filter initialization
  bme.setTemperatureOversampling(BME680_OS_8X);
  bme.setHumidityOversampling(BME680_OS_2X);
  bme.setPressureOversampling(BME680_OS_4X);
  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
  bme.setGasHeater(320, 150); // 320*C for 150 ms

  // 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());

  client.setServer(mqtt_server, 1883);
}

void loop() {

  if (!client.connected()) {
    reconnect();
  }

  StaticJsonDocument<80> doc;
  char output[80];

  long now = millis();
  if (now - lastMsg > 5000) {
    lastMsg = now;
    float temp = bme.readTemperature();
    float pressure = bme.readPressure()/100.0;
    float humidity = bme.readHumidity();
    float gas = bme.readGas()/1000.0;
    doc["t"] = temp;
    doc["p"] = pressure;
    doc["h"] = humidity;
    doc["g"] = gas;

    serializeJson(doc, output);
    Serial.println(output);
    client.publish("/home/sensors", output);
  }
    
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "ESP8266Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      delay(5000);
    }
  }
}