📦 Smart Home Automation System

📘 Complete Integration Code + Blynk Setup

🧠 System Includes

• 🔐 Smart Door Lock (Servo – Manual)

• 🌡 Temperature Monitoring (DHT11)

• ❄ AC Control (Manual + Automatic Mode)

• 💧 Water Tank Monitoring (Ultrasonic)

• 🚰 Pump Control (Manual + Automatic Mode)

• 🔥 Gas Leakage Detection (MQ3 – Safety Override)

• 📱 Full Blynk Dashboard

🟢 PART 1 – Blynk Setup (Step-by-Step)

🔹 Step 1 – Create Template

1. Go to Blynk Cloud

2. Create Template

   • Hardware: ESP32

   • Connection: WiFi

Save.

🔹 Step 2 – Create Datastreams

Create the following:

Save all.

🔹 Step 3 – Dashboard Widgets

Add:

• Gauge → V0 (Temperature)

• Slider → V3 (Temp Setpoint)

• Button → V1 (AC Manual)

• Switch → V2 (AC Mode)

• Gauge → V4 (Water Level)

• Slider → V7 (Water Setpoint)

• Button → V5 (Pump Manual)

• Switch → V6 (Pump Mode)

• Label → V8 (Gas Value)

• Label → V9 (Gas Alert)

• Button → V10 (Door Lock)

🟢 PART 2 – Complete Integrated Code

⚠ Replace WiFi and Blynk credentials.

#define BLYNK_TEMPLATE_ID "YOUR_TEMPLATE_ID"
#define BLYNK_TEMPLATE_NAME "SmartHome"
#define BLYNK_AUTH_TOKEN "YOUR_AUTH_TOKEN"

#include <WiFi.h>
#include <BlynkSimpleEsp32.h>
#include "DHT.h"
#include <ESP32Servo.h>

// WiFi
char ssid[] = "YOUR_WIFI";
char pass[] = "YOUR_PASS";

// Pins
#define DHTPIN 4
#define DHTTYPE DHT11
#define TRIG 5
#define ECHO 18
#define MQ3_PIN 34
#define SERVO_PIN 13
#define AC_RELAY 26
#define PUMP_RELAY 27

DHT dht(DHTPIN, DHTTYPE);
Servo doorServo;
BlynkTimer timer;

// Variables
float temperature;
float waterLevel;
int gasValue;

int acManual = 0;
int acMode = 0;
float tempSetpoint = 28;

int pumpManual = 0;
int pumpMode = 0;
float waterSetpoint = 30;

int doorState = 0;

// ------------------ BLYNK WRITE ------------------

BLYNK_WRITE(V1) { acManual = param.asInt(); }
BLYNK_WRITE(V2) { acMode = param.asInt(); }
BLYNK_WRITE(V3) { tempSetpoint = param.asFloat(); }

BLYNK_WRITE(V5) { pumpManual = param.asInt(); }
BLYNK_WRITE(V6) { pumpMode = param.asInt(); }
BLYNK_WRITE(V7) { waterSetpoint = param.asFloat(); }

BLYNK_WRITE(V10) {
doorState = param.asInt();
if (doorState) doorServo.write(90);
else doorServo.write(0);
}

// ------------------ SENSOR READ ------------------

void readTemperature() {
temperature = dht.readTemperature();
Blynk.virtualWrite(V0, temperature);
}

void readWaterLevel() {
digitalWrite(TRIG, LOW);
delayMicroseconds(2);
digitalWrite(TRIG, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG, LOW);

long duration = pulseIn(ECHO, HIGH);
float distance = duration * 0.034 / 2;

waterLevel = 100 - distance; // adjust based on tank height
Blynk.virtualWrite(V4, waterLevel);
}

void readGas() {
gasValue = analogRead(MQ3_PIN);
Blynk.virtualWrite(V8, gasValue);

if (gasValue > 1200) {
Blynk.virtualWrite(V9, "⚠ GAS LEAK!");
digitalWrite(AC_RELAY, HIGH); // Turn OFF AC
} else {
Blynk.virtualWrite(V9, "Safe");
}
}

// ------------------ CONTROL LOGIC ------------------

void controlAC() {

if (acMode == 0) { // Manual
digitalWrite(AC_RELAY, acManual ? LOW : HIGH);
}

if (acMode == 1) { // Auto
if (temperature > tempSetpoint)
digitalWrite(AC_RELAY, LOW);
else
digitalWrite(AC_RELAY, HIGH);
}
}

void controlPump() {

if (pumpMode == 0) {
digitalWrite(PUMP_RELAY, pumpManual ? LOW : HIGH);
}

if (pumpMode == 1) {
if (waterLevel < waterSetpoint)
digitalWrite(PUMP_RELAY, LOW);
else
digitalWrite(PUMP_RELAY, HIGH);
}
}

// ------------------ SETUP ------------------

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

pinMode(TRIG, OUTPUT);
pinMode(ECHO, INPUT);
pinMode(AC_RELAY, OUTPUT);
pinMode(PUMP_RELAY, OUTPUT);

digitalWrite(AC_RELAY, HIGH);
digitalWrite(PUMP_RELAY, HIGH);

dht.begin();
doorServo.attach(SERVO_PIN);

Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);

timer.setInterval(2000L, readTemperature);
timer.setInterval(2000L, readWaterLevel);
timer.setInterval(2000L, readGas);
timer.setInterval(2000L, controlAC);
timer.setInterval(2000L, controlPump);
}

// ------------------ LOOP ------------------

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

🧠 Code Explanation (Simplified)

• readTemperature() → Sends temperature to Blynk

• readWaterLevel() → Calculates tank level

• readGas() → Safety override

• controlAC() → Manual/Auto AC logic

• controlPump() → Manual/Auto Pump logic

• BLYNK_WRITE() → Receives mobile commands

No delay() used → Non-blocking → Professional.

🔐 Safety Logic

If gas detected:

AC automatically turns OFF
Alert shown in app

Safety has highest priority.

🎓 What Students Learn

• Multi-sensor integration

• Manual vs Automatic logic

• Safety override design

• Modular coding

• Cloud dashboard design

• Professional IoT architecture