MQ-135 Air Quality Sensor

  The MQ-135 gas sensor uses tin oxide (SnO2) as its sensitive material, which has low conductivity in clean air. When the sensor is exposed to polluted air, the conductivity of the sensor increases with the concentration of harmful gases. The MQ-135 sensor is highly sensitive to ammonia (NH3), sulfur compounds, and benzene vapors. It is also ideal for detecting smoke and other harmful gases, making it suitable for a wide range of applications, such as air quality monitoring in both indoor and outdoor environments. This low-cost sensor is effective for detecting multiple hazardous gases, contributing to environmental protection and health safety.

Module Source

Purchase Link: https://detail.tmall.com/item.htm?abbucket=0&id=13302081252&ns=1&spm=a21n57.1.0.0.5668523c1NVcMb
Baidu Netdisk Download Link:
https://pan.baidu.com/s/1B8WhPIzTmWwQsFFVayRpAA?pwd=9966
Password: 9966

Specifications

Operating Voltage: 3.3V-5V

Operating Current: 150MA

Output Methods: DO (Digital Output) AO (Analog Output)

Reading Method: ADC (Analog-to-Digital Converter)

Pin Count: 4 Pins (2.54mm pitch header)

Hardware Connection

• Connect the Vcc pin of the sensor to the 5V power supply of the development board.
• Connect the GND pin of the sensor to the GND of the development board.
• Connect the AO (Analog Output) pin to the A0 analog input pin of the development board.
• Connect the DO (Digital Output) pin to the digital pin 8 of the development board.

Usage Method

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  * Test Hardware: LCSC ColorEasyDuino Development Board
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  * Modification Date: April 8, 2024
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int MQ135_AO_Pin = A0; // 定义空气质量传感器的AO连接到开发板的A0引脚
int MQ135_DO_Pin = 8;  // 定义空气质量传感器的DO连接到开发板的8号引脚
int MQ135Value = 0; // 用于存储空气质量值的变量
#define ADC_MAX_VALUE 1023  //ADC的最大采集值

void setup() {
  Serial.begin(9600); // 开始串行通讯，设置波特率为9600
  pinMode(MQ135_DO_Pin, INPUT_PULLUP);
}

void loop() {
  // 读取状态
  int MQ135State = digitalRead(MQ135_DO_Pin);
  if (MQ135State == LOW) {
    Serial.println("检测到空气质量较差");
  } else {
    Serial.println("检测到空气质量正常");
  }

  MQ135Value = analogRead(MQ135_AO_Pin); // 读取A0引脚的电压值
  Serial.print("空气质量: ");
  Serial.println( MQ135Value); // 将读取的值发送到电脑的串行监视器
  delay(1000); // 延时1秒
}

Usage Testing