🐶 Smart Pet Feeder (Serial Bluetooth Terminal App)

• 📱 Control gate from mobile

• 🔵 Use Bluetooth (no WiFi required)

• 📟 See gate status in app

• 🎮 Send OPEN / CLOSE commands

📦 Components Required

• ESP32

• SG90 Servo Motor

• External 5V supply (recommended)

• Android phone

• Serial Bluetooth Terminal app

🔌 Circuit Connections

Servo → ESP32

⚠ IMPORTANT:
Connect External GND and ESP32 GND together

📲 App Setup (Serial Bluetooth Terminal)

Use:

• Serial Bluetooth Terminal by Kai Morich (Android)

Steps:

1. Install app from Play Store

2. Turn ON Bluetooth

3. Upload code to ESP32

4. Open app

5. Search devices

6. Connect to ESP32 (Default name we set in code)

💻 Complete ESP32 Bluetooth Code

Copy & paste into Arduino IDE:

#include <ESP32Servo.h>
#include "BluetoothSerial.h"

BluetoothSerial SerialBT;
Servo feederServo;

const int servoPin = 18;
int gateState = 0; // 0 = Closed, 1 = Open

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

SerialBT.begin("Smart_Pet_Feeder"); 
feederServo.attach(servoPin);

feederServo.write(0); // Start closed

Serial.println("Bluetooth Pet Feeder Started");
Serial.println("Device Name: Smart_Pet_Feeder");
}
void loop() {

if (SerialBT.available()) {

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

if (command.equalsIgnoreCase("OPEN")) {
openGate();
}
else if (command.equalsIgnoreCase("CLOSE")) {
closeGate();
}
else {
SerialBT.println("Invalid Command! Send OPEN or CLOSE");
}
}
}

void openGate() {
feederServo.write(90);
gateState = 1;

SerialBT.println("Food Gate is OPEN");
}

void closeGate() {
feederServo.write(0);
gateState = 0;

SerialBT.println("Food Gate is CLOSED");
}

🧠 Code Explanation (Line by Line Concept)

1️⃣ Include Required Libraries

• ESP32Servo → Controls servo motor

• BluetoothSerial → Enables Bluetooth communication

2️⃣ Create Objects

• SerialBT → Used for Bluetooth communication

• feederServo → Used to control servo

3️⃣ Start Bluetooth

This sets Bluetooth device name.

When you scan in mobile, you will see:
👉 Smart_Pet_Feeder

4️⃣ Attach Servo

Connects servo to GPIO 18.

5️⃣ Check for Bluetooth Data

Checks if mobile sent any data.

6️⃣ Read Command

Reads message until Enter key.

Example:
OPEN
CLOSE

7️⃣ Compare Commands

Case insensitive:

• open

• OPEN

• Open

All work.

8️⃣ Open Gate Function

Rotates servo to 90°
Gate opens.

9️⃣ Close Gate Function

Rotates servo to 0°
Gate closes.

📱 How to Use in App

After connecting:

Type:

→ App shows: Food Gate is OPEN

Type:

→ App shows: Food Gate is CLOSED

🎯 What Students Learn From This Version

• Bluetooth communication

• Serial data handling

• Mobile app control

• Real-time feedback

• Embedded system wireless control

🚀 Next Level Upgrade Options

Shiv 🔥 You can now upgrade to:

• 🕒 Automatic close after 5 seconds

• 📊 Send gate status continuously

• 🔐 Password protected Bluetooth

• 📱 Custom Android app

• 🌐 Web server control

• 📦 Add food level sensor

• 🧠 Add feeding schedule timer