top of page
MQ-7 Gas Sensor For Carbon Monoxide Detector Module

MQ-7 Gas Sensor For Carbon Monoxide Detector Module

₹121.00Price

🔍 What this sensor is

The MQ-7 Gas Sensor Module is a low-cost carbon monoxide (CO) detector commonly used in Arduino and IoT projects.

👉 It detects:

  • 🫁 Carbon Monoxide (CO) — a dangerous, odorless gas

🧠 Core Concept (VERY IMPORTANT)

👉 This is a heating-type gas sensor (MQ series)

It works using a cyclic heating process:

  • 🔥 High temperature → cleans sensor

  • 🌡️ Low temperature → detects CO

➡️ This makes it more selective to CO compared to other MQ sensors

⚙️ Key Specifications

  • Target Gas: Carbon Monoxide (CO)

  • Detection Range: ~20 – 2000 ppm

  • Operating Voltage: 5V

  • Output:

    • Analog (A0)

    • Digital (D0 with comparator)

  • Preheat Time: ≥ 24–48 hours (important!)

  • Heater Current: ~150 mA

⚡ Working Principle

  • Uses SnO₂ (tin dioxide) sensing layer

  • CO gas reduces sensor resistance

  • Module converts it into voltage

👉 More CO → higher output signal

🔄 Unique Feature (IMPORTANT)

👉 Unlike MQ-2 / MQ-135:

MQ-7 uses two-phase heating cycle:

  • 5V heating (60s) → cleaning phase

  • 1.4V heating (90s) → sensing phase

➡️ Accurate readings only in low-temp phase

⚠️ Most modules don’t control this automatically
👉 You must handle it in code (advanced use)

🔌 Pinout

  • VCC → 5V

  • GND → Ground

  • A0 → Analog output

  • D0 → Digital output (threshold adjustable)

🧠 Output Behavior

CO LevelOutput
LowLow voltage
MediumMedium voltage
HighHigh voltage

👉 Analog output is non-linear

💡 Applications

  • 🏠 Home CO alarm systems

  • 🔥 Fire detection

  • 🚗 Car exhaust monitoring

  • 🏭 Industrial safety

  • 🤖 Air quality projects

⚠️ Important Notes (VERY IMPORTANT)

❗ 1. Requires long preheating

  • Needs 24–48 hours initially
    👉 Otherwise readings are unstable

❗ 2. Not highly accurate

  • Gives approximate ppm, not precise

  • Needs calibration

❗ 3. High power consumption

  • Heater uses significant current
    👉 Not good for battery projects

❗ 4. Cross sensitivity

  • Also reacts to:

    • Hydrogen

    • Methane
      👉 Not 100% CO selective

❗ 5. Temperature cycle control (advanced)

👉 For accurate CO detection:

  • Must control heater voltage cycle
    ➡️ Otherwise readings are less reliable

🆚 MQ-7 vs Other Sensors

SensorGasAccuracyUse
MQ-2Smoke/LPGLowGeneral
MQ-135Air qualityLowBasic AQ
MQ-7COMediumCO detection
SCD40CO₂⭐ HighPrecise CO₂

👍 When to use this

Use MQ-7 if you want:

  • Low-cost CO detection

  • Basic safety systems

  • Arduino beginner projects

👎 When NOT to use

Avoid if:

  • You need precise ppm measurement

  • Battery-powered device

  • Professional safety system

🧠 Final Understanding

👉 This sensor = “low-cost carbon monoxide detector”
👉 Good for learning & basic projects, not industrial accuracy

🚀 Pro Tip

👉 Better setup for air safety:

  • MQ-7 → CO detection

  • ENS160 → VOC + AQI

  • SHT41 → temperature + humidity

➡️ Combined = complete air monitoring system 🔥

Quantity
bottom of page