Importance and Utility of MH-Z19B

The MH-Z19B is a CO2 sensor module that is commonly used in Arduino projects. It is designed to measure the concentration of carbon dioxide in the air, making it a valuable tool for monitoring indoor air quality, controlling ventilation systems, and ensuring a safe and healthy environment.

By detecting the CO2 levels, the MH-Z19B can provide valuable information about the air quality in a room or building. High levels of CO2 can indicate poor ventilation, which can lead to health issues such as headaches, dizziness, and fatigue. With the MH-Z19B, you can easily monitor the CO2 levels and take appropriate actions to maintain a comfortable and healthy environment.

Project: CO2 Monitoring System

In this project, we will create a CO2 monitoring system using the MH-Z19B sensor module and an Arduino board. The main objective of this project is to continuously measure the CO2 levels in a room and display the readings on an LCD screen. Additionally, we will set up an alarm system to alert us when the CO2 levels exceed a certain threshold.

List of Components:

• MH-Z19B CO2 Sensor Module x1 (https://example.com/mh-z19b)
• Arduino Uno x1 (https://example.com/arduino-uno)
• LCD Screen x1 (https://example.com/lcd-screen)
• Jumper Wires x10 (https://example.com/jumper-wires)
• Breadboard x1 (https://example.com/breadboard)

Examples:

Example 1: Reading CO2 Levels

#include <SoftwareSerial.h>

SoftwareSerial co2Serial(10, 11);  // RX, TX

void setup() {
  Serial.begin(9600);
  co2Serial.begin(9600);
}

void loop() {
  if (co2Serial.available()) {
    int response = co2Serial.read();
    if (response == 0xFF) {
      int high = co2Serial.read();
      int low = co2Serial.read();
      int co2 = (high << 8) + low;
      Serial.print("CO2 Level: ");
      Serial.println(co2);
    }
  }
  delay(1000);
}

Explanation:

• We start by including the SoftwareSerial library to establish communication with the MH-Z19B sensor module.
• In the setup function, we initialize the serial communication for both the Arduino and the MH-Z19B module.
• In the loop function, we check if there is any data available from the MH-Z19B module.
• If there is data available, we read the response byte and check if it is the start byte (0xFF).
• If it is the start byte, we read the high and low bytes of the CO2 concentration and calculate the CO2 level.
• We then print the CO2 level to the serial monitor.

Example 2: Setting up an Alarm

#include <SoftwareSerial.h>

SoftwareSerial co2Serial(10, 11);  // RX, TX

const int alarmThreshold = 1000;

void setup() {
  Serial.begin(9600);
  co2Serial.begin(9600);
  pinMode(13, OUTPUT);
}

void loop() {
  if (co2Serial.available()) {
    int response = co2Serial.read();
    if (response == 0xFF) {
      int high = co2Serial.read();
      int low = co2Serial.read();
      int co2 = (high << 8) + low;
      Serial.print("CO2 Level: ");
      Serial.println(co2);

      if (co2 > alarmThreshold) {
        digitalWrite(13, HIGH);
      } else {
        digitalWrite(13, LOW);
      }
    }
  }
  delay(1000);
}

Explanation:

• This example builds upon the previous one by adding an alarm functionality.
• We define a constant variable alarmThreshold to specify the CO2 level at which the alarm should be triggered.
• In the setup function, we initialize the serial communication, as well as set the LED pin as an output.
• In the loop function, we read the CO2 level as before.
• If the CO2 level exceeds the alarm threshold, we turn on the LED (connected to pin 13) to indicate an alarm.
• If the CO2 level is below the threshold, we turn off the LED.