MQ-135 Gas Sensor

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Product Link

MQ-135 Gas SensorOpenELAB

Introduction

The MQ-135 gas sensor is a popular sensor used to detect a wide range of gases including ammonia, sulfide, and benzene steam, as well as smoke and other harmful gases. It is commonly used in air quality monitoring systems and various industrial applications due to its high sensitivity and fast response time.

Features

• High Sensitivity: Detects a wide range of gases with high accuracy.

• Fast Response Time: Quick response to changes in gas concentrations.

• Wide Detection Range: Suitable for detecting ammonia, sulfide, benzene steam, smoke, and other harmful gases.

• Stable and Long Life: Provides stable readings over a long period.

• Simple Interface: Easy to connect to microcontrollers like Arduino and Raspberry Pi.

Specifications

• Operating Voltage: 5V

• Detecting Range: 10-1000 ppm (Ammonia, Benzene, Alcohol)

• Preheat Time: Over 24 hours

• Sensitivity: Adjustable via onboard potentiometer

• Output: Analog (0-5V) and Digital (TTL logic)

Pinout

• VCC: Power supply pin (5V)

• GND: Ground pin

• AO: Analog output pin

• DO: Digital output pin (High/Low signal based on threshold)

Dimensions

• Size: 40.0mm * 21.0mm

• Weight: 5g

How to Use

1. Power the Sensor: Connect the VCC pin to the 5V power supply and the GND pin to the ground.

2. Read Analog Values: Connect the AO pin to an analog input of your microcontroller to read the gas concentration values.

3. Set Threshold: Adjust the onboard potentiometer to set the threshold for the digital output.

4. Read Digital Values: Connect the DO pin to a digital input of your microcontroller to receive high/low signals based on the gas concentration exceeding the set threshold.

5. Code Example: Write a simple program to read the analog and digital values from the sensor and take appropriate actions based on the readings. For example, you can trigger an alarm if the gas concentration exceeds a certain limit.

// Example code for Arduino

int analogPin = A0; // Analog pin connected to AO
int digitalPin = 2; // Digital pin connected to DO

void setup() {
  Serial.begin(9600);
  pinMode(digitalPin, INPUT);
}

void loop() {
  int analogValue = analogRead(analogPin);
  int digitalValue = digitalRead(digitalPin);

  Serial.print("Analog Value: ");
  Serial.println(analogValue);

  if (digitalValue == HIGH) {
    Serial.println("Gas detected!");
  } else {
    Serial.println("No gas detected.");
  }

  delay(1000); // Wait for a second before taking another reading
}