read_mhz14_from_au.ino

#include <cppQueue.h>

#include <SoftwareSerial.h>

// Read data from MH-Z14 CO2 sensor.
// ref. https://www.openhacks.com/uploadsproductos/mh-z14_co2.pdf
// ref. https://gist.github.com/takashiski/3a1c1da6b9aac8863696d960660461f3

// RX: the port recieve bytes from sensor.
// connect to sensor port 19 (TX)
uint8_t co2sRx = 12;
// TX: the port send bytes to sensor
// connect to sensor port 18 (RX)
uint8_t co2sTx = 13;
SoftwareSerial co2Sensor(co2sRx, co2sTx);

byte co2sInitCmd[9] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79};
byte co2sInBuf[9] = {0,0,0,0,0,0,0,0,0};

uint8_t btRx = 8;
// TX: the port send bytes to sensor
// connect to sensor port 19 (RX)
uint8_t btTx = 9;
SoftwareSerial bt(btRx, btTx);

uint8_t interval = 10;

int16_t  co2 = 0;

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

  Serial.println("start to setup.");
  co2Sensor.begin(9600);
  Serial.println("co2Sensor initialized");
}

void loop() {
  co2Sensor.write(co2sInitCmd, 9);
  co2Sensor.flush();

  co2 = 0;


  if (co2Sensor.available()) {
    co2Sensor.readBytes(co2sInBuf,9);

    co2 += co2sInBuf[2] <<8;
    co2 += co2sInBuf[3];

    Serial.println(co2);
  } else {
    Serial.println("co2Sensor is NOT available!");
  }
  delay(interval * 1000);
}