BME680 and ESP8266 Based Indoor Air Quality Monitoring System

Monitoring the air, we breathe indoors is becoming increasingly important, especially in urban environments where pollution levels can impact our health. In this project, we’ll build a smart Indoor Air Quality Monitoring System using the BME680 environmental sensor, ESP8266 Wi-Fi module, and Blynk IoT platform. This compact setup allows real-time tracking of temperature, humidity, barometric pressure, and indoor air quality (VOC levels) right on your smartphone.

🌐 Project Overview

This IoT-based project utilizes the BME680 sensor to measure environmental conditions and sends the data to the Blynk mobile app via the ESP8266 (NodeMCU or Wemos D1 Mini). With just a few components and minimal coding, you can monitor your room’s air quality from anywhere in the world.

🎯 Features

Live temperature, humidity, pressure, and air quality data
Real-time updates every 10 seconds
Remote monitoring via Blynk mobile app
Compact and low-power hardware
Ideal for home, office, or industrial use

🔧 Required Components

Component	Quantity
ESP8266 (NodeMCU / Wemos D1 Mini)	1
BME680 Environmental Sensor	1
Jumper Wires	1 set
Breadboard (optional)	1
Micro USB Cable	1
Smartphone with Blynk App	1

🔌 Circuit Diagram

Connections Between BME680 and ESP8266 (I2C):

BME680 Pin	ESP8266 Pin
VCC	3.3V
GND	GND
SDA	D2 (GPIO4)
SCL	D1 (GPIO5)

Make sure your BME680 module is 3.3V compatible.

🧠 How It Works

BME680 Sensor reads temperature, humidity, pressure, and gas resistance (VOC levels).
ESP8266 connects to Wi-Fi and sends this data to the Blynk Cloud.
The Blynk App displays real-time environmental data on your phone using virtual widgets.

IOT Based Air Quality Monitoring System with ESP32 & BME680 Sensor

📲 Blynk Setup

Install the Blynk App (available on Android and iOS).
Create a new project and select ESP8266 as the device.
Note the Auth Token sent to your email.
Add 4 display widgets:
- V0: Temperature (°C)
- V1: Humidity (%)
- V2: Pressure (hPa)
- V3: Air Quality (kOhms)
Arrange widgets in a clean layout.

🖥️ Code for ESP8266 Microcontroller

Here’s the complete Arduino IDE sketch for the project:

// Tech Trends Shameer
// IoT-Based Pollution Monitoring System Using ESP8266 and BME680

#define BLYNK_TEMPLATE_ID "TMPL3Uj6HgZ6n"
#define BLYNK_TEMPLATE_NAME "Smart Pollution Monitoring"
#define BLYNK_AUTH_TOKEN "fZDiU5kBUuakFTxxdfhgvudl0IE55Vh0He_"

#define BLYNK_PRINT Serial
#include <Adafruit_Sensor.h>
#include <Adafruit_BME680.h>
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

char auth[] = BLYNK_AUTH_TOKEN;
char ssid[] = ""; // Enter your Wi-Fi name
char pass[] = ""; // Enter your Wi-Fi password

Adafruit_BME680 bme;
BlynkTimer timer;

void setup() {
    Serial.begin(115200);

    WiFi.begin(ssid, pass);
    while (WiFi.status() != WL_CONNECTED) {
        delay(1000);
        Serial.println("Connecting to WiFi...");
    }
    Serial.println("Connected to WiFi!");

    Blynk.begin(auth, ssid, pass);

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

    bme.setTemperatureOversampling(BME680_OS_8X);
    bme.setHumidityOversampling(BME680_OS_2X);
    bme.setPressureOversampling(BME680_OS_4X);
    bme.setGasHeater(320, 150); // Heater at 320°C for 150ms

    timer.setInterval(10000L, sendSensorData);
}

void sendSensorData() {
    if (!bme.performReading()) {
        Serial.println("Failed to read BME680 sensor!");
        return;
    }

    float temp = bme.temperature;
    float hum = bme.humidity;
    float press = bme.pressure / 100.0;
    float air_quality = bme.gas_resistance / 1000.0;

    Serial.print("Temperature: "); Serial.print(temp); Serial.println("°C");
    Serial.print("Humidity: "); Serial.print(hum); Serial.println("%");
    Serial.print("Pressure: "); Serial.print(press); Serial.println("hPa");
    Serial.print("Air Quality (VOC): "); Serial.print(air_quality); Serial.println(" kOhms");

    Blynk.virtualWrite(V0, temp);
    Blynk.virtualWrite(V1, hum);
    Blynk.virtualWrite(V2, press);
    Blynk.virtualWrite(V3, air_quality);
}

void loop() {
    Blynk.run();
    timer.run();
}

Let’s break down the air quality monitoring project code using BME680 sensor, ESP8266 board, and Blynk platform to explain everything clearly:

🔧 Code Overview

This project reads environmental data—temperature, humidity, pressure, and air quality (VOC levels)—using a BME680 sensor and sends it to the Blynk IoT app every 10 seconds over Wi-Fi using an ESP8266 microcontroller.

📦 Libraries and Definitions

#define BLYNK_TEMPLATE_ID ...
#define BLYNK_TEMPLATE_NAME ...
#define BLYNK_AUTH_TOKEN ...

These are Blynk-specific IDs that connect your device to the correct template in the Blynk app.

#define BLYNK_PRINT Serial
#include <Adafruit_Sensor.h>
#include <Adafruit_BME680.h>
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

Adafruit_Sensor.h and Adafruit_BME680.h: Libraries to interact with the BME680 environmental sensor.
ESP8266WiFi.h: Lets the ESP8266 connect to Wi-Fi.
BlynkSimpleEsp8266.h: Handles communication between your ESP8266 and the Blynk cloud.

🔐 Credentials

char auth[] = BLYNK_AUTH_TOKEN;
char ssid[] = "Your SSID";
char pass[] = "Your Password";

Replace ssid and pass with your Wi-Fi name and password.
auth is the authentication token from Blynk.

🌡️ Sensor and Timer Initialization

Adafruit_BME680 bme;
BlynkTimer timer;

bme: An object to handle the BME680 sensor.
timer: A Blynk helper that helps call functions at regular intervals.

🔁 setup() Function

Serial.begin(115200);

Starts serial communication at 115200 baud rate for debugging.

🌐 Wi-Fi Connection

WiFi.begin(ssid, pass);
while (WiFi.status() != WL_CONNECTED) { ... }

Loops until the ESP8266 connects to the internet.

📲 Blynk Initialization

Blynk.begin(auth, ssid, pass);

Starts the connection to the Blynk cloud using Wi-Fi and the authentication token.

📡 BME680 Sensor Setup

if (!bme.begin()) { ... }

Initializes the sensor and halts execution if it’s not found.

bme.setTemperatureOversampling(BME680_OS_8X);
bme.setHumidityOversampling(BME680_OS_2X);
bme.setPressureOversampling(BME680_OS_4X);
bme.setGasHeater(320, 150);  // Heater temp = 320°C for 150ms

These settings improve measurement accuracy and enable the gas (VOC) sensor part of the BME680.

⏲️ Data Transmission Timer

timer.setInterval(10000L, sendSensorData);

Calls sendSensorData() every 10 seconds (10000 ms).

📤 sendSensorData() Function

if (!bme.performReading()) { ... }

Checks if the sensor is able to take a new reading.

float temp = bme.temperature;
float hum = bme.humidity;
float press = bme.pressure / 100.0;
float air_quality = bme.gas_resistance / 1000.0;

Reads:

Temperature in °C
Humidity in %
Pressure in hPa
Air quality (VOC gas resistance) in kOhms (higher = cleaner air)

🔄 Debug Output

Prints all readings to the serial monitor.

📱 Send to Blynk App

Blynk.virtualWrite(V0, temp);
Blynk.virtualWrite(V1, hum);
Blynk.virtualWrite(V2, press);
Blynk.virtualWrite(V3, air_quality);

Sends sensor values to virtual pins V0–V3. In the Blynk app, these can be linked to display widgets like Gauges or Graphs.

🔄 loop() Function

Blynk.run();
timer.run();

Keeps Blynk connected.
Runs the timer to ensure periodic updates.

📲 Setting up ESP8266 Board

Enter your Wi-Fi credentials and Blynk Auth Token.
Flash this code onto an ESP8266 board (like NodeMCU or Wemos D1 Mini).
Connect a BME680 sensor to the ESP8266 (typically via I2C).

📊 Sensor Output Interpretation

Temperature (°C): Measures ambient temperature.
Humidity (%RH): Shows how moist the air is.
Pressure (hPa): Useful for weather predictions.
Air Quality (kΩ): Based on VOC gas resistance — higher = cleaner air.

Note: BME680 does not output AQI directly. The gas resistance value can be used to estimate air quality with additional algorithms or libraries (e.g., Bosch BSEC).

✅ Benefits of This Project

Affordable and compact solution
Great for home automation or smart homes
Helps identify when ventilation is needed
Can be expanded with alerts, data logging, or integration with home assistants

🚀 Possible Improvements

Use ESP32 for more power and Bluetooth support
Integrate Bosch BSEC library for more accurate IAQ (Indoor Air Quality) index
Add an OLED display for local monitoring
Send alerts via email or push notification

🏁 Conclusion

With this simple yet powerful setup, you can keep tabs on your indoor environment and take proactive steps to improve air quality. Whether you want to monitor a bedroom, lab, office, or workshop — this BME680 + ESP8266 IoT Air Quality Monitor is a smart addition to your living space.