MQ-7 Carbon Monoxide Gas Sensor Module (Silent Killer Gas Leak Detector)
Protect your household and industrial environments from invisible hazards with the industrial-grade MQ-7 Carbon Monoxide Gas Sensor Module. Specifically engineered to identify the presence of Carbon Monoxide, this module utilizes an advanced internal sensing element that experiences low conductivity in clean air but spikes sharply as Carbon Monoxide concentrations rise.
Carbon Monoxide is often called the "silent killer" because it is a completely colorless, odorless, and tasteless gas produced by incomplete combustion. To tackle this, the MQ-7 utilizes a high-and-low temperature cycling method to accurately detect this specific hazard. It serves as an essential safety monitor for smart home safety grids, indoor air quality stations, vehicle exhaust monitors, and boiler room alarm panels.
Key Features
Carbon Monoxide Focus: Highly sensitive to Carbon Monoxide gas while maintaining very low cross-sensitivity to standard alcohol fumes, cooking smoke, and general combustible gases.
Dual Output Architecture: Built with both a Digital Output for instantaneous high/low safety alarm triggers and an Analog Output for real-time parts-per-million concentration mapping.
Adjustable Alarm Threshold: Features an onboard multi-turn potentiometer, allowing you to finely adjust the digital trigger point to match your specific clean-air background baseline.
Onboard Voltage Comparator: Assembled with a highly stable comparator integrated circuit, ensuring clean, sharp digital square waves that eliminate false triggers.
Explosion-Proof Stainless Steel Mesh: Designed with a dual-layer stainless steel mesh cover that protects the internal heated filament while preventing external spark risks.
Real-Time LED Status Monitoring: Equipped with two independent indicators—one for central power tracking and another that lights up instantly when Carbon Monoxide levels pass your preset safety limit.
Technical Specifications
Feature | Specification |
Sensor Type | Semiconductor Gas Sensor (MQ-7) |
Target Gas | Carbon Monoxide Gas |
Operating Voltage | 5V DC Nominal |
Heater Cycling Logic | High Cycle (5V for Combustible Cleaning) | Low Cycle (1.5V for Carbon Monoxide Detection) |
Detection Concentration Range | 10 to 1000 ppm (Parts-Per-Million) |
Output Type | Dual Output: Analog Output + Digital Output |
Active Logic State | Digital Output drops LOW (0V) when gas thresholds are crossed |
Mounting Layout | Pre-drilled screw holes for secure panel or wall attachment |
Board Dimensions | 32 mm x 20 mm x 22 mm |
Hardware Wiring & Pin Mapping
The module breaks out a 4-pin interface that maps directly to standard microcontrollers like Arduino, ESP32, STM32, and Raspberry Pi:
VCC: Connects to a stable +5V DC power supply rail. (Requires a dedicated 5V source to correctly heat the internal filament).
GND: System Ground Reference.
DO (Digital Output): Outputs a stable High/Low logic level. Connect this straight to a digital input or hardware interrupt pin. It stays HIGH in standard conditions and drops LOW when dangerous Carbon Monoxide limits are crossed.
AO (Analog Output): Outputs a varying voltage signal corresponding directly to the concentration of Carbon Monoxide in the air. Connect this to an analog pin to process exact parts-per-million calculations.
Common Applications
Smart Home Fire & Gas Alarms: Deploy near fireplaces, kitchen stoves, attached garages, or gas water heaters to instantly trigger sound buzzers if a Carbon Monoxide leak occurs.
Commercial Parking & Garages: Monitors indoor automotive garages and tunnels where vehicle exhaust can cause toxic carbon monoxide build-ups.
Boiler & Furnace Rooms: Serves as a reliable safety backup monitor to ensure commercial heating systems are venting combustion gases safely out of the building.
Portable Environmental Dataloggers: Build compact, battery-powered safety badges or hand-held devices for industrial inspection workers.
💡 Operating Tip: The MQ-7 sensor requires a "Preheat / Burn-in" period before it can output accurate readings. After powering the module on for the very first time, let it sit powered up for 24 to 48 hours to balance the internal chemical sensing element. For subsequent uses, allow 1 to 2 minutes of warm-up time until the heater stabilizes. The module will become warm to the touch during normal operation—this is perfectly normal behavior for the internal heater loop.
Package Includes:
1 x MQ-7 Carbon Monoxide Gas Sensor Module (4-Pin Breakout Board)