MQ135 Air Quality Sensor Module Harmful Gas Detection Ammonia (NH3), Nitrogen Oxides (NOx), Alcohol, Benzene Vapours, Smoke, Carbon Dioxide (CO2)

Description

What it is

The MQ135 air quality sensor module is a device for detecting harmful gases, ideal for environmental monitoring projects. The sensor can detect various types of gases and vapors.

Features

• Detects ammonia (NH₃)
• Detects nitrogen oxides (NOx)
• Detects alcohol, benzene vapors, and smoke
• Detects carbon dioxide (CO2)

What it is for

This sensor can be used to build alarm systems that send email notifications when harmful gas levels are high. It is compatible with Arduino and ESP.

Tutorial: How to use the MQ135 sensor (air quality module)

The MQ135 module detects harmful gases such as NH3, NOx, and CO2. Ideal for environmental monitoring projects.

What you need

• Arduino Uno
• USB cable
• 5V power supply
• MQ135 module

Steps

1. Connect VCC to the +5V of the Arduino
2. Connect GND to the ground of the Arduino
3. Connect AO (analog) to an analog pin of Arduino, e.g., A0
4. Upload the sketch with the provided code
5. Check the read values on Serial Monitor

Example code

void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(A0);
  Serial.println(sensorValue);
}

Mini project

Build a harmful gas alarm system that sends email notifications when levels are high.

Common mistakes

• Connect the module with a different voltage than supported
• Do not verify data readings on Serial Monitor
• Use AO as a digital pin
• Ignore the datasheet specifications

Recommended accessories

• LCD module for direct data display
• Portable 5V battery for external power supply
• Relay module to activate devices automatically
• ESP8266 WiFi module to send data online

Frequently asked questions

How can I calibrate the sensor?
Calibrate the sensor by exposing it to known gases and recording the values.

What is the detection range?
Check the specific datasheet for precise details.