High Sensitivity CO Carbon Monoxide Sensor Detector MQ-7

MQ-7 Carbon Monoxide (CO) Sensor
The sensor utilizes Tin Dioxide (SnO_2) as its sensing material. To function correctly, it cycles between two temperatures: a high-temperature phase to "clean" the sensor and a low-temperature phase to "detect" the CO molecules.

Why the MQ-7 is a Life-Saving Essential:
• CO Specialization: It is tuned to be highly sensitive to Carbon Monoxide while ignoring common household gases like LPG or Methane that might trigger false alarms in other sensors.
• Wide Detection Range: It can detect CO concentrations from 20 to 2000 ppm. Since human health issues begin at concentrations as low as 50–100 ppm, this sensor provides ample early warning.
• Dual Output Utility:
* Analog (A0): Provides a variable voltage proportional to the CO level. This is used to track "ppm" levels over time.
* Digital (D0): Acts as an immediate threshold trigger. Using the onboard potentiometer, you can set a specific safety limit that, when crossed, instantly alerts a microcontroller.
• Industrial and Domestic Versatility: It is robust enough for industrial monitoring but small and affordable enough for DIY home security projects.

Technical Capabilities:
• Dual-Stage Heating:
* High Heat (5V): For 60 seconds (cleans the sensor by evaporating accumulated gases).
* Low Heat (1.5V): For 90 seconds (the actual measurement phase where CO is detected).
• High Sensitivity: Capable of detecting very low concentrations of CO that are otherwise impossible for humans to sense.
• Operating Voltage: 5V (standard for the module).

Best For:
The MQ-7 is the primary choice for domestic CO alarms, car cabin air quality monitors, industrial chimney monitoring, and portable safety devices for fire investigators or HVAC technicians.