فنون
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حِرَف
الثقافة والتاريخ
ترفيه
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الطعام والمشروبات
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الهندسة العكسية
العلوم
رياضة
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Building a Methane Gas Leak Detector
Ed

أنشأه

Ed

13. يوليو 2026FI
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Building a Methane Gas Leak Detector

Build a circuit that sniffs out methane — the main component of natural gas — and alarms when it rises. An MQ-4 sensor's reading climbs when combustible gas is present; the Arduino compares it to clean air and triggers a buzzer and red LED. A great combustible-gas sensing project — with two honest notes: methane is flammable, and this is a demonstration, NOT a certified gas-leak detector.

متوسط
1-2 hours

التعليمات

1

Wire the sensor, buzzer and LED

On the breadboard: MQ-4 VCC to Arduino 5V, GND to GND, and its analog output (AOUT) to A0. Active buzzer + to pin 8, - to GND. Red LED anode to pin 7 through a 330 Ω resistor, cathode to GND.

المواد لهذه الخطوة:

Arduino Uno R3Arduino Uno R31 قطعة
Methane CNG Gas Sensor - MQ-4Methane CNG Gas Sensor - MQ-41 قطعة
Active Buzzer Module (5V, 5-Pack)Active Buzzer Module (5V, 5-Pack)1 قطعة
LED - Basic 5mmLED - Basic 5mm1 قطعة
Resistor 330 Ohm 1/6 Watt PTH - 20 packResistor 330 Ohm 1/6 Watt PTH - 20 pack1 عبوة
BreadboardBreadboard1 قطعة
Jumper Wires (Male-to-Male)Jumper Wires (Male-to-Male)1 عبوة
2

Connect and open the IDE

Plug the Arduino into your computer with the USB cable, open the Arduino IDE, and select Arduino Uno and its serial port.

المواد لهذه الخطوة:

USB-B CableUSB-B Cable1 قطعة

الأدوات المطلوبة:

Computer with Arduino IDEComputer with Arduino IDE
3

Upload the detector sketch

Paste this sketch and upload. It warms the sensor, records a clean-air baseline, then sounds the buzzer and lights the LED whenever the reading rises above that baseline.

methane_detector.inoarduino
// Methane / natural-gas leak INDICATOR using an MQ-4 sensor.
// NOT a certified gas-leak detector - see the safety note. Methane is flammable.
// MQ-4 analog output on A0; buzzer on pin 8; red warning LED on pin 7.

const int MQ4_PIN = A0;
const int BUZZER_PIN = 8;
const int LED_PIN = 7;

int cleanAirValue = 0;          // baseline, measured at startup
const int ALARM_MARGIN = 150;   // how far above baseline triggers the alarm

void setup() {
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(9600);

  Serial.println("Warming up the MQ-4 (2 min) in clean air...");
  delay(120000);
  cleanAirValue = analogRead(MQ4_PIN);
  Serial.print("Clean-air baseline: ");
  Serial.println(cleanAirValue);
}

void loop() {
  int reading = analogRead(MQ4_PIN);
  Serial.println(reading);

  if (reading > cleanAirValue + ALARM_MARGIN) {
    digitalWrite(LED_PIN, HIGH);      // combustible gas above baseline -> alarm
    digitalWrite(BUZZER_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  }
  delay(500);
}
4

Warm up, baseline and test SAFELY

Power it in fresh air and let the 2-minute warm-up set the baseline (a new MQ-4 also needs a 24–48 h burn-in). Test with only a TINY controlled source in a well-ventilated room — a brief puff of gas from an UNLIT lighter held near the sensor. NEVER test with a real gas leak, a large amount of gas, or anywhere near a flame or spark. Adjust ALARM_MARGIN for sensitivity.

5

Safety limits

Methane is highly flammable and, in enough concentration, explosive. This circuit is a LEARNING project and at best a supplementary indicator — it is NOT a certified gas-leak detector: the hobby MQ-4 gives a relative reading, not calibrated ppm, drifts, and needs re-baselining. For real protection use a certified natural-gas detector, and if you ever smell gas, do not switch anything on or off — leave and call your gas utility.

المواد

8

الأدوات المطلوبة

1
التكلفة الإجمالية المقدرة
$56.00

المخططات ذات الصلة

هذه المخططات تشارك المعرفة مع هذا — التقنيات والمواد والمبادئ

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CC0 ملكية عامة

هذا المخطط مُصدر بموجب CC0. يحق لك نسخه وتعديله وتوزيعه واستخدامه لأي غرض، دون طلب إذن.

ادعم الصانع بشراء منتجات عبر مخططه حيث يكسب عمولة الصانع يحددها البائعون، أو أنشئ نسخة جديدة من هذا المخطط وضمّنه كرابط في مخططك لمشاركة الإيرادات.

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