💧 Smart Water Management System (Serial Bluetooth Terminal)

This version will:

• Show water level in mobile app

• Work in AUTO + MANUAL mode

• Allow motor ON/OFF from phone

• Send warning when tank FULL

• Protect motor from dry run

No WiFi required ✅
No internet required ✅

📦 Components Used

• ESP32

• Water Level Sensor (Analog)

• Single Channel Relay

• DC Water Pump

• Android phone with Serial Bluetooth Terminal app

Recommended App:
👉 Serial Bluetooth Terminal by Kai Morich

🔌 Connections

1️⃣ Water Level Sensor

2️⃣ Relay Module

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

💻 COMPLETE BLUETOOTH CODE (AUTO + MANUAL)

Copy & paste into Arduino IDE:

#include <BluetoothSerial.h>

BluetoothSerial SerialBT;

#define WATER_SENSOR 34
#define RELAY_PIN 26

int waterValue = 0;

bool autoMode = true;
bool motorState = false;

int lowLevel = 1000; 
int fullLevel = 3000;

void setup() {
Serial.begin(115200);
SerialBT.begin("Smart_Water_System");

pinMode(RELAY_PIN, OUTPUT);
digitalWrite(RELAY_PIN, HIGH); // Motor OFF

Serial.println("Bluetooth Water Management Started");
}

void loop() {

waterValue = analogRead(WATER_SENSOR);

// Send water value to Bluetooth app
SerialBT.print("Water Level: ");
SerialBT.println(waterValue);

// Check Bluetooth Commands
if (SerialBT.available()) {

String command = SerialBT.readStringUntil('\n');
command.trim();

if (command.equalsIgnoreCase("AUTO")) {
autoMode = true;
SerialBT.println("Switched to AUTO Mode");
}

else if (command.equalsIgnoreCase("MANUAL")) {
autoMode = false;
SerialBT.println("Switched to MANUAL Mode");
}

else if (command.equalsIgnoreCase("ON") && !autoMode) {
turnMotorOn();
}

else if (command.equalsIgnoreCase("OFF") && !autoMode) {
turnMotorOff();
}

else {
SerialBT.println("Invalid Command!");
}
}

// AUTO MODE LOGIC
if (autoMode) {

if (waterValue < lowLevel && !motorState) {
SerialBT.println("Water LOW -> Motor ON");
turnMotorOn();
}

if (waterValue > fullLevel && motorState) {
SerialBT.println("Tank FULL -> Motor OFF");
turnMotorOff();
SerialBT.println("WARNING: Tank Full!");
}
}

delay(2000);
}

void turnMotorOn() {
digitalWrite(RELAY_PIN, LOW);
motorState = true;
SerialBT.println("Motor is ON");
}

void turnMotorOff() {
digitalWrite(RELAY_PIN, HIGH);
motorState = false;
SerialBT.println("Motor is OFF");
}