DIY Gas Sensor Project with ESP32: Smoke Detection

Detect harmful gases or smoke in real time using ESP32 and an MQ-2 sensor — view alerts instantly! by YaranaIoT Guru

BeginnerFull instructions provided8 hours8

DIY Gas Sensor Project with ESP32: Smoke Detection

Things used in this project

Software apps and online services

Arduino IDE

Story

One day, Rohan noticed smoke in his kitchen but realized it too late. After that incident, he wanted to make something simple yet smart — an IoT smoke detector.He found YaranaIoT Guru’s tutorials and built a system that instantly alerts him when gas or smoke levels rise beyond safety limits.

“Now, even if I’m not home, my ESP32 sends me an alert whenever gas levels increase — safety made simple!”

“Now, even if I’m not home, my ESP32 sends me an alert whenever gas levels increase — safety made simple!”

🧰 Components Required

💻 Code Example

/*
  DIY Gas Sensor Project with ESP32: Smoke Detection
  Author: YaranaIoT Guru
*/

#include <WiFi.h>
#include <WebServer.h>

const char* ssid = "YourWiFiName";
const char* password = "YourWiFiPassword";

WebServer server(80);

const int gasPin = 34;   // Analog input from MQ-2
const int buzzer = 25;
const int led = 26;

int gasValue = 0;
int threshold = 500;  // Adjust as needed

String buildPage() {
  String html = "<html><head><meta charset='UTF-8'><title>ESP32 Gas Monitor</title>";
  html += "<meta name='viewport' content='width=device-width, initial-scale=1'>";
  html += "<style>body{text-align:center;font-family:Arial;background:#f4f4f4;}h2{color:#333;}p{font-size:20px;}</style></head><body>";
  html += "<h2>🔥 ESP32 Gas & Smoke Detection</h2><p>Gas Level: " + String(gasValue) + "</p>";
  if (gasValue > threshold) html += "<p style='color:red;'>⚠️ DANGER: Gas Level High!</p>";
  else html += "<p style='color:green;'>✅ Safe Environment</p>";
  html += "<p><small>By YaranaIoT Guru</small></p></body></html>";
  return html;
}

void handleRoot() {
  server.send(200, "text/html", buildPage());
}

void setup() {
  Serial.begin(115200);
  pinMode(buzzer, OUTPUT);
  pinMode(led, OUTPUT);

  WiFi.begin(ssid, password);
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }
  Serial.println("\nConnected! IP: " + WiFi.localIP().toString());
  server.on("/", handleRoot);
  server.begin();
}

void loop() {
  gasValue = analogRead(gasPin);
  Serial.println(gasValue);

  if (gasValue > threshold) {
    digitalWrite(buzzer, HIGH);
    digitalWrite(led, HIGH);
  } else {
    digitalWrite(buzzer, LOW);
    digitalWrite(led, LOW);
  }

  server.handleClient();
  delay(1000);
}