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ESP32-Based Smart Air Purifier with Wi-Fi and Blynk Integration

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Smart Air Purifier Circuit Documentation

Summary

This document provides a detailed overview of a smart air purifier circuit. The circuit uses an ESP32 microcontroller to monitor indoor air quality, control a fan, and integrate with the Blynk app for real-time monitoring. The system includes various sensors and components to measure air quality, temperature, humidity, and control a fan based on the air quality index (AQI).

Component List

  1. ESP32

    • Description: Microcontroller with WiFi and Bluetooth capabilities.
    • Pins: EN, VP, VN, D34, D35, D32, D33, D25, D26, D27, D14, D12, D13, GND, VIN, 3V3, D15, D2, D4, RX2, TX2, D5, D18, D19, D21, RX0, TX0, D22, D23, BOOT

  2. DHT22

    • Description: Temperature and humidity sensor.
    • Pins: +, Out, -

  3. MQ-7 Breakout

    • Description: Carbon monoxide (CO) gas sensor.
    • Pins: VCC, GND, DO, AO

  4. 12v PWM Fan (120mm)

    • Description: Fan with PWM control for speed adjustment.
    • Pins: GND, +12V, TACH, PWM

  5. Adafruit MOSFET Driver

    • Description: MOSFET driver for controlling high-power devices.
    • Pins: GND, V+, In, Out

  6. LED: Two Pin (red)

    • Description: Red LED indicator.
    • Pins: cathode, anode

  7. 12v Battery

    • Description: 12V power source.
    • Pins: -, +

  8. 5v Battery

    • Description: 5V power source.
    • Pins: +, -

  9. Resistor

    • Description: 300 Ohms resistor.
    • Pins: pin1, pin2

  10. PM2.5 Air Quality Sensor and Breadboard Adapter Kit - PMS5003

    • Description: Particulate matter sensor for measuring PM2.5 levels.
    • Pins: VCC, GND, SET, RX, TX, RST

  11. Toggle Switch SPST

    • Description: Single-pole single-throw toggle switch.
    • Pins: L1, COM

Wiring Details

ESP32

DHT22

MQ-7 Breakout

12v PWM Fan (120mm)

Adafruit MOSFET Driver

LED: Two Pin (red)

12v Battery

5v Battery

Resistor

PM2.5 Air Quality Sensor and Breadboard Adapter Kit - PMS5003

Toggle Switch SPST

Documented Code

// Smart Air Purifier Code with Blynk Integration in C
// This program uses an ESP32 microcontroller to monitor indoor air quality, adjust purification settings, and integrate with the Blynk app for real-time monitoring.

#include <WiFi.h>
#include <BlynkSimpleEsp32.h>
#include <DHT.h>

// Blynk Configuration
char auth[] = "Your_Blynk_Auth_Token";
char ssid[] = "YourWiFiSSID";
char pass[] = "YourWiFiPassword";

// Pins Configuration
#define DHT_PIN 4          // Pin for temperature and humidity sensor
#define PM_SENSOR_PIN 36   // Pin for particulate matter sensor (AQI)
#define FAN_PWM_PIN 18     // Pin for fan control
#define FILTER_LIFE_PIN 34 // Pin for filter life sensor
#define MODE_SWITCH_PIN 25 // Pin for manual mode switch
#define LED_INDICATOR_PIN 2

// Initialize Sensors and Components
DHT dht(DHT_PIN, DHT22);

// Variables
int fan_speed = 0;
int aqi = 0;
int filter_status = 0;

// Function Prototypes
void connectWifi();
void updateSensors();
void controlFan();

// Blynk Virtual Pin Handlers
BLYNK_WRITE(V0) {
  fan_speed = param.asInt();
  ledcWrite(0, fan_speed);
}

BLYNK_WRITE(V1) {
  digitalWrite(LED_INDICATOR_PIN, param.asInt());
}

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);

  // Initialize Pins
  pinMode(FILTER_LIFE_PIN, INPUT);
  pinMode(MODE_SWITCH_PIN, INPUT);
  pinMode(LED_INDICATOR_PIN, OUTPUT);

  // Initialize DHT Sensor
  dht.begin();

  // Initialize PWM for Fan Control
  ledcSetup(0, 1000, 8); // Channel 0, 1kHz, 8-bit resolution
  ledcAttachPin(FAN_PWM_PIN, 0);

  // Connect to WiFi and Blynk
  connectWifi();
  Blynk.begin(auth, ssid, pass);
}

void loop() {
  Blynk.run();
  updateSensors();
  controlFan();
  delay(5000); // Wait 5 seconds between updates
}

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

void updateSensors() {
  // Read DHT Sensor
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Read PM Sensor and Filter Life Sensor
  aqi = analogRead(PM_SENSOR_PIN);
  filter_status = analogRead(FILTER_LIFE_PIN);

  // Send data to Blynk
  Blynk.virtualWrite(V2, temperature);
  Blynk.virtualWrite(V3, humidity);
  Blynk.virtualWrite(V4, aqi);
  Blynk.virtualWrite(V5, filter_status);

  // Notify if filter needs replacement
  if (filter_status < 500) {
    Blynk.notify("Filter replacement required!");
  }

  // Debug Output
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.print(" C, Humidity: ");
  Serial.print(humidity);
  Serial.print(" %, AQI: ");
  Serial.print(aqi);
  Serial.print(", Filter Status: ");
  Serial.println(filter_status);
}

void controlFan() {
  // Adjust fan speed based on AQI
  if (aqi < 50) {
    fan_speed = 64; // Low speed
  } else if (aqi < 100) {
    fan