#include <WiFi.h>
#include <ESP32Servo.h>

const char* ssid = "Pet_Feeder_AP";
const char* password = "12345678";

WiFiServer server(23); // Telnet Port

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

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

feederServo.attach(servoPin);
feederServo.write(0); // Start Closed

// Start Access Point
WiFi.softAP(ssid, password);

Serial.println("Access Point Started");
Serial.print("AP IP Address: ");
Serial.println(WiFi.softAPIP());

server.begin();
Serial.println("Server Started on Port 23");
}

void loop() {

WiFiClient client = server.available();

if (client) {
Serial.println("Client Connected");

client.println("Welcome to Smart Pet Feeder");
client.println("Type OPEN or CLOSE");

while (client.connected()) {

if (client.available()) {

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

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

client.stop();
Serial.println("Client Disconnected");
}
}

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

client.println("Food Gate is OPEN");
Serial.println("Gate Opened");
}

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

client.println("Food Gate is CLOSED");
Serial.println("Gate Closed");
}

🧠 Code Explanation (Clear Concept Teaching)

1️⃣ Create Hotspot

ESP32 becomes a WiFi router.

Mobile will see:
👉 Pet_Feeder_AP

Password:
👉 12345678

2️⃣ Get AP IP Address

Default IP usually:

You will use this in mobile app.

3️⃣ Create TCP Server

Port 23 is Telnet communication port.

4️⃣ Wait for Client

Checks if mobile connected.

5️⃣ Read Commands

Reads user message.

6️⃣ Control Servo

OPEN → 90°
CLOSE → 0°

📱 How To Use (Step-by-Step)

Step 1

Upload code

Step 2

Open Serial Monitor
You will see:

Step 3

Go to Mobile WiFi
Connect to:

Password:

Step 4

Open TCP Client App

Enter:

• Host: 192.168.4.1

• Port: 23

Click Connect

Step 5

Send Command

Type:

Response:

Type:

Response:

🎯 What Students Learn From This Version

• Access Point Mode

• Client-Server concept

• TCP communication

• Wireless embedded systems

• Real-world IoT architecture

• Offline IoT systems

🚀 Why This Version Is Powerful

✔ No router required
✔ No internet required
✔ Works anywhere
✔ Ideal for rural demo
✔ Professional IoT concept