💧 Smart Water Management System

(ESP32 + Water Level Sensor + Relay + Blynk IoT)

This version supports:

• ✅ AUTO Mode

• ✅ MANUAL Mode

• ✅ Motor ON/OFF from Blynk dashboard

• ✅ Real-time water level monitoring

• ✅ Tank FULL warning

• ✅ Cloud control from anywhere

Internet required ✔
Blynk IoT Cloud required ✔

📦 Components Required

• ESP32

• Water Level Sensor (Analog)

• Single Channel Relay

• DC Water Pump

• WiFi Connection

• Blynk IoT Account

🔌 Connections

🔹 Water Level Sensor

🔹 Relay Module

⚠ Relay Active LOW
LOW → Motor ON
HIGH → Motor OFF

🌐 Blynk IoT Setup (Step-by-Step)

Go to:
👉 https://blynk.cloud

Login and follow below steps.

🔹 Step 1 – Create Template

1. Click New Template

2. Template Name:

    

    

   Smart Water System

    

3. Hardware: ESP32

4. Connection Type: WiFi

5. Click Done

🔹 Step 2 – Create Datastreams

Go to Datastreams → New Datastream

1️⃣ V0 – Auto/Manual Mode Switch

• Type: Virtual Pin

• Pin: V0

• Data Type: Integer

• Min: 0

• Max: 1

• Default: 1

👉 1 = AUTO
👉 0 = MANUAL

2️⃣ V1 – Motor Control Button

• Type: Virtual Pin

• Pin: V1

• Data Type: Integer

• Min: 0

• Max: 1

👉 1 = Motor ON
👉 0 = Motor OFF

3️⃣ V2 – Water Level Value

• Type: Virtual Pin

• Pin: V2

• Data Type: Integer

Used to display sensor reading.

4️⃣ V3 – Tank Full LED

• Type: Virtual Pin

• Pin: V3

• Data Type: Integer

👉 1 = Tank Full
👉 0 = Normal

🔹 Step 3 – Create Device

1. Go to Devices

2. Click New Device

3. From Template

4. Select Smart Water System

5. Copy Auth Token

You will paste it in code.

📱 Dashboard Setup (Mobile App)

Open Blynk App.

Add Widgets:

🔘 Switch (Auto/Manual)

• Datastream: V0

• Mode: Switch

🔘 Button (Motor Control)

• Datastream: V1

• Mode: Switch

📊 Value Display (Water Level)

• Datastream: V2

💡 LED Widget (Tank Full)

• Datastream: V3

• ON Color: Red

• OFF Color: Green

💻 COMPLETE FINAL CODE (Blynk IoT Version)

Install Libraries:

• Blynk

Replace credentials before uploading.

#define BLYNK_TEMPLATE_ID "YOUR_TEMPLATE_ID"
#define BLYNK_DEVICE_NAME "Smart Water System"
#define BLYNK_AUTH_TOKEN "YOUR_AUTH_TOKEN"

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

#define WATER_SENSOR 34
#define RELAY_PIN 26

char ssid[] = "YOUR_WIFI_NAME";
char pass[] = "YOUR_WIFI_PASSWORD";

bool autoMode = true;
bool motorState = false;

int lowLevel = 1000;
int fullLevel = 3000;

BLYNK_WRITE(V0) {
autoMode = param.asInt();
}

BLYNK_WRITE(V1) {
if (!autoMode) {
int value = param.asInt();
if (value == 1) {
turnMotorOn();
} else {
turnMotorOff();
}
}
}

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

pinMode(RELAY_PIN, OUTPUT);
digitalWrite(RELAY_PIN, HIGH);

Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);
}

void loop() {
Blynk.run();

int waterValue = analogRead(WATER_SENSOR);
Blynk.virtualWrite(V2, waterValue);

if (autoMode) {

if (waterValue < lowLevel && !motorState) {
turnMotorOn();
}

if (waterValue > fullLevel && motorState) {
turnMotorOff();
Blynk.virtualWrite(V3, 1);
} else {
Blynk.virtualWrite(V3, 0);
}
}
}

void turnMotorOn() {
digitalWrite(RELAY_PIN, LOW);
motorState = true;
Blynk.virtualWrite(V1, 1);
}

void turnMotorOff() {
digitalWrite(RELAY_PIN, HIGH);
motorState = false;
Blynk.virtualWrite(V1, 0);
}

🧠 Code Explanation

1️⃣ BLYNK_WRITE(V0)

Controls Auto/Manual mode from dashboard.

2️⃣ BLYNK_WRITE(V1)

Controls motor manually when Auto mode is OFF.

3️⃣ Water Level Reading

Sends value to V2 for display.

4️⃣ Auto Mode Logic

If water LOW → Motor ON
If tank FULL → Motor OFF + LED ON

5️⃣ Blynk.virtualWrite()

Updates dashboard widgets in real time.

📟 System Working Flow

1. ESP32 connects to WiFi

2. Connects to Blynk Cloud

3. Reads water level

4. Checks mode

5. Controls motor

6. Updates dashboard

🎯 What Students Learn

• IoT cloud architecture

• Virtual pins concept

• Remote automation

• Real-time data monitoring

• Auto + Manual embedded system design