IoT Home Monitoring and Automation System

IoT Home Monitoring and Automation System

Introduction

This project will create a smart home system using the ESP32 microcontroller. The system will:

• Monitor environment variables: temperature, humidity, and light intensity.
• Control appliances: using relays for connected devices like lights and fans.
• Send data to a cloud platform for real-time monitoring and visualization.
• Allow control via a mobile app (Blynk or a custom-developed app).

Real-world Applications:

• Home automation
• Smart offices
• Remote environmental monitoring
• Energy-saving systems

Learning Objectives

By the end of this project, you will learn:

• How to interface sensors and relays with ESP32.
• Use the ESP32 for wireless communication (Wi-Fi).
• Send sensor data to a cloud platform (e.g., ThingSpeak or Blynk).
• Control appliances remotely through a mobile app.
• Build an efficient and reliable circuit for IoT applications.

Tools and Components

Hardware

• ESP32 Dev Module (1x)
• DHT22 (or DHT11) Temperature and Humidity Sensor (1x)
• LDR (Light Dependent Resistor) for light intensity sensing (1x)
• 10kΩ Resistor (for the LDR circuit)
• Relay Module (2-channel) for appliance control
• Breadboard and connecting wires
• 5V Power Supply
• Appliances for control (e.g., LED lamp, fan)

Software

• Arduino IDE (for programming the ESP32)
• Blynk mobile app or ThingSpeak (for cloud monitoring)
• Serial Monitor (for testing and debugging)

Background and Definitions

• ESP32: A powerful microcontroller with built-in Wi-Fi and Bluetooth capabilities, ideal for IoT applications.
• DHT22 Sensor: Measures temperature and humidity with good accuracy.
• LDR: A Light Dependent Resistor whose resistance decreases with increasing light intensity.
• Relay Module: Acts as a switch to control high-power appliances.

Circuit Diagram Explanation

The circuit is divided into two parts: sensor connections and appliance control. Here’s how the components will be connected:

1. ESP32 Pin Configuration:
   • DHT22 → GPIO 4
   • LDR (through a voltage divider) → GPIO 36 (Analog Input)
   • Relay 1 (for light) → GPIO 25
   • Relay 2 (for fan) → GPIO 26
2. Power Supply:
   • The ESP32 is powered via a 5V USB supply.
   • The relay module is powered using the 5V pin on the ESP32.

Circuit Diagram Description:

• The DHT22 sensor has three pins: VCC, GND, and DATA. Connect DATA to GPIO 4.
• For the LDR, use a 10kΩ resistor in a voltage divider configuration. The analog voltage from this divider is fed to GPIO 36.
• The relay module control pins are connected to GPIO 25 and GPIO 26 to control the light and fan, respectively.

Step-by-Step Guide

1. Install ESP32 Board in Arduino IDE
   Follow these steps to install ESP32 support in Arduino IDE:
   • Open Arduino IDE and go to File > Preferences.
   • In the Additional Board Manager URLs, add this link:
     https://dl.espressif.com/dl/package_esp32_index.json
   • Go to Tools > Board > Board Manager and install “esp32 by Espressif Systems”.
2. Connect the Hardware
   Assemble the circuit as per the diagram described earlier. Ensure the following:
   • The power supply is stable.
   • Use proper connections for the relay to avoid short circuits.
3. Write the Code
   Upload the following code to your ESP32 using the Arduino IDE.

Source Code

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

#define DHTPIN 4
#define DHTTYPE DHT22
#define LIGHT_SENSOR_PIN 36
#define RELAY1 25
#define RELAY2 26

char auth[] = "YOUR_BLYNK_AUTH_TOKEN";
char ssid[] = "YOUR_WIFI_SSID";
char pass[] = "YOUR_WIFI_PASSWORD";

DHT dht(DHTPIN, DHTTYPE);
BlynkTimer timer;

void setup() {
  Serial.begin(115200);
  dht.begin();
  pinMode(RELAY1, OUTPUT);
  pinMode(RELAY2, OUTPUT);
  WiFi.begin(ssid, pass);
  Blynk.begin(auth, ssid, pass);

  timer.setInterval(2000L, sendSensorData);
}

void sendSensorData() {
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();
  int lightLevel = analogRead(LIGHT_SENSOR_PIN);

  if (isnan(temp) || isnan(hum)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  Blynk.virtualWrite(V1, temp);
  Blynk.virtualWrite(V2, hum);
  Blynk.virtualWrite(V3, lightLevel);

  Serial.print("Temp: ");
  Serial.print(temp);
  Serial.print(" °C, Humidity: ");
  Serial.print(hum);
  Serial.print(" %, Light: ");
  Serial.println(lightLevel);
}

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

Testing and Debugging Tips

1. Sensor Readings Not Showing:
   • Check the wiring of the DHT22 and ensure it’s getting power.
   • Use the Serial Monitor to verify sensor output.
2. Relay Not Switching:
   • Verify relay module connections.
   • Check that GPIO pins 25 and 26 are configured correctly.
3. Wi-Fi Connection Issues:
   • Ensure the SSID and password are correct.
   • Bring the ESP32 closer to the Wi-Fi router for better signal strength.

Extensions and Future Enhancements

• Add more sensors: Motion sensors, gas sensors, or water leakage sensors for a comprehensive smart home system.
• Control via voice commands: Integrate with Google Assistant or Alexa.
• Data logging: Store sensor data in a database for long-term monitoring.
• Energy efficiency analysis: Use the data to create reports on power usage.