This is a simple-to-use Carbon Monoxide (CO) sensor, suitable for sensing CO concentrations in the air.
The MQ-7 can detect CO-gas concentrations anywhere from 20 to 2000ppm.

This sensor has a high sensitivity and fast response time.
The sensor's output is an analog resistance.
The drive circuit is very simple; all you need to do is power the heater coil with 5V, add a load resistance, and connect the output to an ADC.

This sensor comes in a package similar to our MQ-3 alcohol sensor

 

Documents:

• Datasheet
• Wiring Example