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mq135-air-quality-en.md

Air Safety: The MQ-135 Gas Sensor

The MQ-135 Gas Sensor is a versatile air quality monitor capable of detecting a wide range of gases, including Ammonia (NH3), Nitrogen Oxides (NOx), Alcohol, Benzene, smoke, and CO2. It is an essential component for building a home air quality station.

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How It Works: Chemical Resistance

The sensor uses a small heating element and an electrochemical sensor. When it's exposed to clean air, the conductivity is low. As the concentration of target gases increases, the conductivity of the sensor increases, letting more current flow. The Arduino reads this as a changing analog voltage.

Project Features

  • PPM Measurement: While difficult to calibrate perfectly without professional equipment, the sensor can give you a relative PPM (Parts Per Million) reading.
  • Threshold Alarms: You can program a buzzer to sound if the air quality drops below a safe level.
  • Preheating: Note that this sensor requires a "warm-up" period (typically 24-48 hours of initial burn-in and then 2 minutes every time it's powered) to give stable readings.

Hardware Components

  • Arduino Uno/Nano: To read the analog signal.
  • MQ-135 Sensor Module: The primary hardware.
  • Piezo Buzzer: For audio alerts.
  • 10k-ohm Potentiometer: To adjust sensitivity (if using a pre-made module).

Building this project is a great way to learn about chemistry in electronics and the importance of environmental monitoring.

ข้อมูล Frontmatter ดั้งเดิม 

title: "Air Quality Monitor: MQ-135 Gas Sensor"
description: "Breathe safer! Learn how to use the MQ-135 sensor with Arduino to detect harmful gases and monitor air quality in your home or office."
category: "Sensors & Environment"
difficulty: "Easy"