MQ-7 CO Carbon Monoxide Coal Gas Sensor Module

The MQ-7 CO Carbon Monoxide Coal Gas Sensor Module is a widely used sensor for detecting carbon monoxide (CO) gas, particularly in environments where this toxic gas might be present.

Here’s an overview of the MQ-7 sensor module:

• Purpose: It has a high sensitivity to carbon monoxide gas.
• Sensitivity: It has a high sensitivity to methane and other combustible gases.
• Principle: The sensor operates on the principle of a semiconductor gas sensor, where the resistance of the sensing material changes based on the concentration of CO gas.

Features:

• Analog and Digital Output: Similar to other MQ series sensors, the MQ-7 module provides both analog and digital outputs. The analog output can be used to estimate the gas concentration, while the digital output can be configured to trigger alerts when CO concentration exceeds a predefined threshold.
• Adjustable Sensitivity: Many modules include a potentiometer that allows users to adjust the sensor’s sensitivity.
• Affordability: The MQ-7 sensor module is cost-effective, making it a popular choice for gas detection projects.

Using the MQ-7:

• Powering the Sensor: The sensor typically requires a 5V DC power supply.
• Calibration: To achieve accurate readings, calibration may be necessary. This involves exposing the sensor to clean air to establish a baseline resistance value.
• Reading Values: Like previous MQ series sensors, you can use a microcontroller (such as Arduino) to read values from the MQ-7 sensor. Connect the analog output to an analog pin and the digital output to a digital input pin on the microcontroller.

Technical Details

• Model: MQ-7
• Operating voltage (v): DC 5
• Range: 10 ~ 1000 ppm
• Characteristic gas: 100 ppm CO
• Sensitivity : ≥ 3%.
• Return time: ≤ 30 sec
• Heating resistance: ± 31 Ω
• Heating current: ≤ 180 mA
• Heating voltage : 5.0V ± 2V / 1.5 ± 1V
• Heating power: approx. 350 mW
• Ambient temperature (°C) : -20 ~ + 50
• Humidity: ≤ 95% RH
• Oxygen content: 21%.

Physical Attributes: MQ-7 Sensor Module

• Length * Width * Height (mm): 32 x 20 x 15
• Weight (gm): 7

Package Includes

• 1 x MQ-7 CO Carbon Monoxide Coal Gas Sensor Module