MQ-7 Gas Sensor Module For Carbon Monoxide Detector Module
☠️ MQ-7 Gas Sensor Module
📌 Overview
The MQ-7 Gas Sensor Module is specifically designed to detect Carbon Monoxide (CO), a toxic and odorless gas.
👉 Commonly used in:
🏠 Home safety systems
🚗 Car exhaust monitoring
🏭 Industrial environments
🤖 IoT gas detection projects
🧠 Working Principle
Uses SnO₂ (Tin Dioxide) sensing layer
In clean air → low conductivity
In presence of CO → conductivity increases
👉 The sensor converts this into an analog voltage signal
⚠️ Special feature:
Uses dual heating cycle
🔥 High temp (~5V) → cleans sensor
🌡 Low temp (~1.5V) → detects CO accurately
📊 Infographic Summary
┌──────────────────────────────┐
│ ☠️ MQ-7 CO GAS SENSOR │
├──────────────────────────────┤
│ 🎯 Detects: Carbon Monoxide │
│ ⚡ Voltage: 5V │
│ 📏 Range: 20–2000 ppm │
│ 🔌 Output: Analog + Digital │
│ 🔥 Type: Toxic gas sensor │
│ 🔁 Dual heating cycle │
└──────────────────────────────┘
🔌 Pin Configuration
┌──────────────┐
│ MQ-7 Module │
├──────────────┤
│ VCC → 5V
│ GND → Ground
│ AO → Analog
│ DO → Digital
└──────────────┘
⚙️ Key Specifications
⚡ Operating Voltage: 5V DC
📏 Detection Range: 20 – 2000 ppm CO
🔌 Output:
Analog (CO concentration level)
Digital (threshold detection)
🔥 Heater Current: ~150 mA
🌡 Operating Temperature: -10°C to 50°C
🌟 Key Features
☠️ High sensitivity to Carbon Monoxide
⚡ Fast response time
🔧 Easy to interface
💰 Low cost
🔁 Adjustable sensitivity (potentiometer)
🧪 Applications
🚨 CO leakage alarm systems
🚗 Vehicle exhaust monitoring
🏠 Smart home safety devices
🏭 Industrial gas detection
🤖 IoT environmental monitoring
🔗 Interfacing
Compatible with:
🔵 Arduino
📡 ESP32 / ESP8266
🍓 Raspberry Pi
👉 Use:
AO → measure CO level
DO → trigger alarm
⚠️ Important Notes
⏳ Requires preheating (24–48 hours)
⚠️ Needs heater voltage cycling for accuracy
⚠️ Not highly selective (may respond to other gases)
⚠️ High power consumption
🚨 Safety tip:
Carbon monoxide is deadly—always use certified detectors for real-life safety systems
🆚 MQ-7 vs Other MQ Sensors
| Sensor | Detects |
|---|---|
| MQ-2 | Smoke + LPG |
| MQ-4 | Methane (CNG) |
| MQ-6 | LPG |
| MQ-7 | Carbon Monoxide (CO) |
💡 Pro Tip
For a CO safety project:
MQ-7 + Buzzer 🔊 + LED 💡 + Microcontroller
👉 Trigger alarm instantly when CO is detected
