Published February 28, 2026 © MIT

IoT-Based Smart Stray Animal Water Feeder System

An IoT-based smart water feeder that automatically refills and monitors water for stray animals. 🐶💧

BeginnerFull instructions provided7 hours71

IoT-Based Smart Stray Animal Water Feeder System

Things used in this project

Software apps and online services

Arduino IDE

Story

🌍 1️⃣ Introduction

Garmi ke time me stray animals sabse zyada suffer karte hain.Paani ki kami unke liye life-threatening ho sakti hai.

Common problems:

Bowl jaldi khali ho jata hai

Bowl jaldi khali ho jata hai

Koi refill nahi karta

Koi refill nahi karta

Dirty water issue

Dirty water issue

Overflow waste

Overflow waste

Is problem ka smart solution:

🐶 Smart Stray Animal Water Feeder

🐶 Smart Stray Animal Water Feeder

Ek IoT-based automatic water monitoring & refill system.

💡 2️⃣ System Overview

✔ Water level monitoring✔ Automatic refill✔ Overflow protection✔ Remote monitoring✔ Solar-powered option

🧰 3️⃣ Required Hardware

3.1️⃣ ESP32 (Main Controller)

Use:Main controller, WiFi communication, pump control logic.

3.2️⃣ Ultrasonic Sensor (HC-SR04)

Use:Water level distance measure karta hai.

3.3️⃣ 5V Mini Water Pump

Use:Automatic refill ke liye.

3.4️⃣ Relay Module (1 Channel)

Use:Pump ON/OFF control.

3.5️⃣ Water Container / Bowl

Use:Water storage.

3.6️⃣ Solar Panel (Optional)

Use:Outdoor sustainable power.

🔌 4️⃣ Circuit Diagram

🔗 5️⃣ Wiring Table

Ultrasonic Sensor → ESP32

VCC → 5VGND → GNDTrig → GPIO5Echo → GPIO18

Relay → ESP32

IN → GPIO4VCC → 5VGND → GND

Pump → Relay Output

⚙️ 6️⃣ Working Logic

1️⃣ Ultrasonic sensor water level measure karta hai2️⃣ Agar level low → Relay ON3️⃣ Pump start4️⃣ Tank full detect → Pump OFF5️⃣ Cloud update (optional)

🚀 7️⃣ Key Features

✔ Automatic refill✔ Overflow protection✔ Remote monitoring✔ Low water alert✔ Solar-ready design✔ Outdoor durable

🌎 8️⃣ Applications

✔ Street animals✔ Animal shelters✔ NGOs✔ Public parks✔ Smart city initiatives

✔ CSR project✔ NGO deployment✔ Sponsorship-based feeder✔ Smart city integration✔ Community welfare device

📞 1️⃣0️⃣ Project Support

Complete project, PCB, enclosure design, IoT dashboard & deployment available.

📲 WhatsApp: +91 9336183481

🏁 1️⃣1️⃣ Conclusion

Smart Stray Animal Water Feeder ensures:

✔ Continuous clean water✔ Humane care✔ Smart automation✔ Sustainable solution

Technology + Compassion ❤️🐶

🐶 Smart Stray Animal Water Feeder ✅ Complete ESP32 Code

#include <WiFi.h>
#include <PubSubClient.h>

// ----------------------
// Pin Configuration
// ----------------------
#define TRIG_PIN 5
#define ECHO_PIN 18
#define RELAY_PIN 4

// ----------------------
// WiFi Credentials
// ----------------------
const char* ssid = "YOUR_WIFI_NAME";
const char* password = "YOUR_WIFI_PASSWORD";

// ----------------------
// MQTT Configuration
// ----------------------
const char* mqtt_server = "broker.hivemq.com";
const char* topic_level = "animalfeeder/waterlevel";
const char* topic_status = "animalfeeder/pumpstatus";

WiFiClient espClient;
PubSubClient client(espClient);

// ----------------------
// Water Level Threshold (in cm)
// ----------------------
float tankHeight = 20.0;       // Total tank height
float lowLevelThreshold = 12.0; // When to start pump
float fullLevelThreshold = 5.0; // When to stop pump

// ----------------------
// Setup Function
// ----------------------
void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);

  digitalWrite(RELAY_PIN, HIGH);  // Relay OFF initially (active LOW)

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("\nWiFi Connected");

  client.setServer(mqtt_server, 1883);
}

// ----------------------
// MQTT Reconnect
// ----------------------
void reconnect() {
  while (!client.connected()) {
    client.connect("AnimalWaterFeeder");
  }
}

// ----------------------
// Ultrasonic Distance Read Function
// ----------------------
float getDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

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

  return distance;
}

// ----------------------
// Main Loop
// ----------------------
void loop() {

  if (!client.connected()) {
    reconnect();
  }

  client.loop();

  float distance = getDistance();

  Serial.print("Water Level Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  client.publish(topic_level, String(distance).c_str());

  // ----------------------
  // Pump Logic
  // ----------------------

  if (distance > lowLevelThreshold) {
    // Water Low → Pump ON
    digitalWrite(RELAY_PIN, LOW);
    Serial.println("Pump ON");
    client.publish(topic_status, "Pump ON");
  }

  if (distance <= fullLevelThreshold) {
    // Tank Full → Pump OFF
    digitalWrite(RELAY_PIN, HIGH);
    Serial.println("Pump OFF");
    client.publish(topic_status, "Pump OFF");
  }

  delay(3000);
}