🔥 Introduction to the Humanoid Fire Fighter Robot

Fire accidents in homes, schools, and hospitals are dangerous, and sending humans inside to extinguish them can be life-threatening. What if we could send a robot instead? In this exciting project, we will build a humanoid fire fighter robot that can be controlled wirelessly using your smartphone.

This isn’t just a simple car; it’s designed to look like a humanoid robot, complete with a “head” that holds a camera for live video streaming and a “body” that carries a water tank and a Bluetooth speaker for making emergency announcements. By using the NodeMCU ESP8266, we can control the robot’s movement and water pump from a safe distance over Wi-Fi. This is an excellent project for science exhibitions and Class 10–12 STEM submissions.

🧠 What You Will Learn

📦 Components Needed

To build this robot, you will need the following electronic components and materials. You can find most of these on the STEM ROBO HUB store.

⚙️ How It Works

The core of the robot is the NodeMCU ESP8266. It connects to your mobile phone via Wi-Fi and creates a web server (or connects to an app like Blynk). When you press buttons on your phone screen, the NodeMCU receives the commands and instructs the L298N motor driver to spin the motors forward, backward, left, or right.

For the fire-fighting mechanism, a 5V water pump is connected to a relay or transistor controlled by the NodeMCU. When you press the “Extinguish” button on your app, the pump activates, spraying water through a pipe mounted on the robot’s arm. Additionally, a small Bluetooth speaker on the robot allows you to play recorded voice messages like “Evacuate immediately!” from your phone, making it a true rescue robot.

🛠️ Step-by-Step Build

🔌 Circuit Diagram

Follow these connections carefully to ensure your robot works correctly.

Figure 1: Wiring diagram for NodeMCU, L298N, and Water Pump

• Motors to L298N: Connect left motors to OUT1 & OUT2; right motors to OUT3 & OUT4.
• L298N to NodeMCU:
  • IN1 → D1 (GPIO 5)
  • IN2 → D2 (GPIO 4)
  • IN3 → D3 (GPIO 0)
  • IN4 → D4 (GPIO 2)
• Water Pump: Connect the pump through a Relay Module or a TIP122 transistor. Connect the Relay Signal pin to NodeMCU D5 (GPIO 14).
• Power: Connect the 7.4V (2x Li-ion) battery pack to the 12V and GND terminals of the L298N. Connect the L298N’s 5V output to the NodeMCU VIN pin to power the microcontroller.

💻 Code

We will use a simple Web Server code. This code creates buttons on a webpage to control the robot and the pump. Upload this using the Arduino IDE.

#include 

const char* ssid = "FireFighterBot";  // Name of your Robot's Wi-Fi
const char* password = "12345678";    // Password

WiFiServer server(80);

// Motor Pins
int IN1 = 5;  // D1
int IN2 = 4;  // D2
int IN3 = 0;  // D3
int IN4 = 2;  // D4

// Pump Pin
int PUMP = 14; // D5

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

pinMode(IN1, OUTPUT);
pinMode(IN2, OUTPUT);
pinMode(IN3, OUTPUT);
pinMode(IN4, OUTPUT);
pinMode(PUMP, OUTPUT);

// Stop everything initially
digitalWrite(IN1, LOW);
digitalWrite(IN2, LOW);
digitalWrite(IN3, LOW);
digitalWrite(IN4, LOW);
digitalWrite(PUMP, HIGH); // Assuming Relay is Active LOW

// Connect to Wi-Fi
Serial.println();
Serial.print("Configuring access point...");
WiFi.softAP(ssid, password);
IPAddress myIP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(myIP);
server.begin();
Serial.println("HTTP server started");
}

void loop() {
WiFiClient client = server.available();
if (!client) {
return;
}

String request = client.readStringUntil('\r');
client.flush();

// Control Logic
if (request.indexOf("/FORWARD") != -1) {
digitalWrite(IN1, HIGH); digitalWrite(IN2, LOW);
digitalWrite(IN3, HIGH); digitalWrite(IN4, LOW);
}
else if (request.indexOf("/BACKWARD") != -1) {
digitalWrite(IN1, LOW); digitalWrite(IN2, HIGH);
digitalWrite(IN3, LOW); digitalWrite(IN4, HIGH);
}
else if (request.indexOf("/LEFT") != -1) {
digitalWrite(IN1, LOW); digitalWrite(IN2, HIGH);
digitalWrite(IN3, HIGH); digitalWrite(IN4, LOW);
}
else if (request.indexOf("/RIGHT") != -1) {
digitalWrite(IN1, HIGH); digitalWrite(IN2, LOW);
digitalWrite(IN3, LOW); digitalWrite(IN4, HIGH);
}
else if (request.indexOf("/STOP") != -1) {
digitalWrite(IN1, LOW); digitalWrite(IN2, LOW);
digitalWrite(IN3, LOW); digitalWrite(IN4, LOW);
}
else if (request.indexOf("/PUMP_ON") != -1) {
digitalWrite(PUMP, LOW); // Turn Relay ON
}
else if (request.indexOf("/PUMP_OFF") != -1) {
digitalWrite(PUMP, HIGH); // Turn Relay OFF
}

// Serve the HTML Page
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("");
client.println("");
client.println("");
client.println("

");
client.println("

");
}

⚠️ Troubleshooting

❓ FAQ