BME680 Sensors

main.cpp

#include <Arduino.h>
#include <WiFi.h>
#include <PubSubClient.h>
#include <Wire.h>
#include <Adafruit_BME680.h>
#include <Adafruit_Sensor.h>

// WiFi SSID / Password
#define wifi_ssid     "[WIFI_SSID]"
#define wifi_password "[WIFI_PASS]"

// MQTT Broker IP address, username, password, and client ID
#define mqtt_server   "[IP_ADDRESS]"
#define mqtt_user     "[USERNAME]"
#define mqtt_password "[PASSWORD]"
#define mqtt_clientid "ESP32Client1"

// Sensor MQTT Topics
#define temperature_topic "livingroom/temperature"
#define humidity_topic    "livingroom/humidity"
#define pressure_topic    "livingroom/pressure"
#define gas_topic         "livingroom/gas"
#define output_topic      "livingroom/output"

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;

// BME680 sensor SPI pins
#include <SPI.h>
#define BME_SCK   18
#define BME_MISO  19
#define BME_MOSI  23
#define BME_CS    5

//Adafruit_BME680 bme(BME_CS); // hardware SPI
Adafruit_BME680 bme(BME_CS, BME_MOSI, BME_MISO, BME_SCK); // software SPI

// Declare floats
float temperature = 0;
float humidity = 0;
float pressure = 0;
float gas = 0;

// LED Pin
const int ledPin = 2;

void setup_wifi() {
  delay(10);
  // Connect to WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(wifi_ssid);

  WiFi.begin(wifi_ssid, wifi_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* message, unsigned int length) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageTemp;
  
  for (int i = 0; i < length; i++) {
    Serial.print((char)message[i]);
    messageTemp += (char)message[i];
  }
  Serial.println();

  // If a message is received on the topic */output, you check if the message is either "on" or "off". 
  // Changes the output state according to the message
  if (String(topic) == output_topic) {
    Serial.print("Changing output to ");
    if(messageTemp == "on"){
      Serial.println("on");
      digitalWrite(ledPin, HIGH);
    }
    else if(messageTemp == "off"){
      Serial.println("off");
      digitalWrite(ledPin, LOW);
    }
  }
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect(mqtt_clientid, mqtt_user, mqtt_password)) {
      Serial.println("connected");
      // Subscribe
      client.subscribe(output_topic);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  // default settings
  // (you can also pass in a Wire library object like &Wire2)
  //status = bme.begin();  
  if (!bme.begin(0x76)) {
    Serial.println("Could not find a valid BME680 sensor, check wiring!");
    while (1);
  }
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);

  pinMode(ledPin, OUTPUT);
}

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

  long now = millis();
  if (now - lastMsg > 5000) {
    lastMsg = now;
    
    // Temperature in Celsius
    //temperature = bme.readTemperature();
    // Temperature in Fahrenheit 
    temperature = 1.8 * bme.readTemperature() + 32; // Temperature in Fahrenheit
    
    // Convert the value to a char array
    char tempString[8];
    dtostrf(temperature, 1, 2, tempString);
    Serial.print("Temperature: ");
    Serial.println(tempString);
    client.publish(temperature_topic, tempString);

    humidity = bme.readHumidity();
    
    // Convert the value to a char array
    char humString[8];
    dtostrf(humidity, 1, 2, humString);
    Serial.print("Humidity: ");
    Serial.println(humString);
    client.publish(humidity_topic, humString);

    pressure = bme.readPressure();

    // Convert the value to a char array
    char presString[6];
    dtostrf(pressure, 1, 0, presString);
    Serial.print("Pressure: ");
    Serial.println(presString);
    client.publish(pressure_topic, presString);

    gas = bme.readGas();

    // Convert the value to a char array
    char gasString[5];
    dtostrf(gas, 1, 0, gasString);
    Serial.print("Gas: ");
    Serial.println(gasString);
    client.publish(gas_topic, gasString);
  }
}