ИСКУССТВО
КРАСОТА И ЗДОРОВЬЕ
РЕМЕСЛО
КУЛЬТУРА И ИСТОРИЯ
РАЗВЛЕЧЕНИЯ
ЭКОЛОГИЯ
ЕДА И НАПИТКИ
ЗЕЛЁНОЕ БУДУЩЕЕ
ОБРАТНАЯ ИНЖЕНЕРИЯ
НАУКИ
СПОРТ
ТЕХНОЛОГИИ
НОСИМЫЕ УСТРОЙСТВА
Building a Carbon Monoxide Detector
Ed

Создано

Ed

13. июль 2026FI
6
0
0
0
0

Building a Carbon Monoxide Detector

Build a circuit that senses carbon monoxide (CO) — the invisible, odourless gas from any incomplete combustion — and raises an alarm when it rises. An MQ-7 sensor gives the Arduino a reading that climbs with CO; the code compares it to a clean-air baseline and triggers a buzzer and red LED. A great way to learn gas sensing — but read the safety note: this is a demonstration, NOT a certified life-safety CO alarm.

Средний
1-2 hours

Инструкции

1

Wire the sensor, buzzer and LED

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

Материалы для этого шага:

Arduino Uno R3Arduino Uno R31 штука
Carbon Monoxide Sensor - MQ-7Carbon Monoxide Sensor - MQ-71 штука
Active Buzzer Module (5V, 5-Pack)Active Buzzer Module (5V, 5-Pack)1 штука
LED - Basic 5mmLED - Basic 5mm1 штука
Resistor 330 Ohm 1/6 Watt PTH - 20 packResistor 330 Ohm 1/6 Watt PTH - 20 pack1 штука
BreadboardBreadboard1 штука
Jumper Wires (Male-to-Male)Jumper Wires (Male-to-Male)1 упаковка
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.

Материалы для этого шага:

USB-B CableUSB-B Cable1 штука

Необходимые инструменты:

Computer with Arduino IDEComputer with Arduino IDE
3

Upload the detector sketch

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

co_detector.inoarduino
// Carbon monoxide INDICATOR using an MQ-7 sensor.
// NOT a certified life-safety alarm - see the blueprint's safety note.
// MQ-7 analog output on A0; buzzer on pin 8; red warning LED on pin 7.

const int MQ7_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-7 (2 min) in clean air...");
  delay(120000);                // 2-minute warm-up
  cleanAirValue = analogRead(MQ7_PIN);
  Serial.print("Clean-air baseline: ");
  Serial.println(cleanAirValue);
}

void loop() {
  int reading = analogRead(MQ7_PIN);
  Serial.println(reading);

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

Warm up, baseline and test

Power it in fresh air and let the 2-minute warm-up set the clean-air baseline (a brand-new MQ-7 also needs a longer 24–48 h burn-in before its readings settle). Then hold a small CO source nearby in a ventilated room — the smoke from a just-blown-out match works — and the buzzer and LED should trigger. Change ALARM_MARGIN to make it more or less sensitive.

5

Important safety limits

This is a LEARNING project and, at best, a supplementary indicator — it is NOT a certified life-safety device. A hobby MQ-7 gives a relative reading, not a calibrated ppm; it drifts over time and needs regular re-baselining, and it also responds to smoke and other gases. Carbon monoxide is invisible, odourless and can be fatal: for real protection always use a UL- or EN-certified CO alarm. Never rely on this circuit to keep anyone safe.

Материалы

8

Требуемые инструменты

1
Предполагаемая сумма
$58.00

Связанные чертежи

Эти чертежи делятся знаниями — техники, материалы или принципы

Building an Ultrasonic Parking Sensorот Ed
Blinking LED — Your First Arduino Projectот Admiral OOM

Related blueprints

Other builds that share materials, tools, or techniques with this one.

Building a Methane Gas Leak Detectorelectronics
Building an Ultrasonic Parking Sensorelectronics
Building an Air-Quality Monitorelectronics
Building an Infrared Distance Sensorelectronics
Controlling a Stepper Motor with an EasyDriverelectronics
Controlling a DC Motor with an L298N Driverelectronics

CC0 Общественное достояние

Этот чертёж выпущен под лицензией CC0. Вы можете свободно копировать, изменять, распространять и использовать эту работу в любых целях без запроса разрешения.

Поддержите мейкера, покупая товары через его чертёж, где он получает Комиссию мейкера установленную продавцами, или создайте новую итерацию этого чертежа и включите его как связь в свой чертёж для распределения дохода.

Обсуждение

(0)

Войти чтобы присоединиться к обсуждению

Загрузка комментариев...