MQ-7 CO Gas Detection Sensor Module MQ-7
The MQ-7 Gas Sensor is a widely used sensor module designed for the detection of Carbon Monoxide (CO) concentrations in the air. It utilizes a sensitive SnO₂ (Tin Dioxide) semiconductor layer whose conductivity changes with CO gas concentration. This property allows the sensor to provide a proportional analog output signal that can be read by a microcontroller or ADC for real-time monitoring.
The MQ-7 operates in a cyclical heating mode — alternating between high and low temperatures — to achieve selective detection of CO while minimizing interference from other gases. At high temperatures, the sensor cleans itself to remove contaminants, while at low temperatures, it measures CO levels with high accuracy.
With its wide detection range (20 to 2000 ppm), high sensitivity, and long lifespan, the MQ-7 is ideal for applications such as gas leak detection, air quality monitoring, industrial safety systems, and home security alarms. It is easy to interface with Arduino, Raspberry Pi, and other microcontroller platforms.
Built with a robust metal oxide sensor, stainless steel mesh cover, and durable plastic base, the MQ-7 offers reliability and stability in both indoor and outdoor environments.
Features
High sensitivity to Carbon Monoxide (CO) gas
Wide detection range: 20–2000 ppm
Fast response time and recovery time
Analog voltage output for easy microcontroller interface
Cyclic heating operation for improved accuracy
Long lifespan with reliable performance
Low cost and easy integration
Stable output with minimal drift
Compact and durable metal oxide sensor design
Specifications
| Property | Value |
|---|---|
| Model | MQ-7 |
| Gas Detected | Carbon Monoxide (CO) |
| Detection Range | 20 – 2000 ppm |
| Sensitivity | ≥ 10 mV/ppm CO |
| Sensor Type | Semiconductor (SnO₂) |
| Operating Voltage | 5V DC |
| Heating Voltage | 5V DC / 1.5V DC (cycle operation) |
| Load Resistance | Adjustable (10 kΩ typical) |
| Preheat Time | 24 hours |
| Response Time | ≤ 60 seconds |
| Recovery Time | ≤ 60 seconds |
| Operating Temp | -20°C to 50°C ‘ |
| Operating Humidity | 15% – 90% RH (non-condensing) |
| Life Expectancy | ≥ 5 years in clean air |
| Output | Analog voltage |
| Dimensions | ~32 × 20 × 22 mm |
Applications
Home Safety Alarms – Detect dangerous CO levels
Industrial Safety Systems – Monitor gas leaks in factories and warehouses
Air Quality Monitoring – Track CO concentration in closed environments
Portable Gas Detectors – Handheld monitoring devices for field use
Automotive Applications – Detect CO in vehicle exhaust systems
Smart Home Systems – Integration with IoT platforms for automated alerts
HVAC Systems – Monitor indoor air for safety and comfort
