TM_MH_Z19_Class.cpp

/*
Class for reading a MH-Z19 CO2 sensor
Based on MHZ19 BasicExample
*/

#include "TM_Device_Class.h"
#include "TM_MH_Z19_Class.h"

#include <Arduino.h>
#include "MHZ19.h" // TM: in MHZ19.h ensure to disable printing via #define MHZ19_ERRORS 0

// #define RX_PIN 16
// #define TX_PIN 17
#define MHZ19_BAUDRATE 9600 // Device to MH-Z19 Serial baudrate (should not be changed)

// Initialisierungsliste
TM_MH_Z19_Class::TM_MH_Z19_Class(const uint8_t rx, const uint8_t tx, const bool this_verbose) : TM_Sensor_Device_Class("MH-Z19B", this_verbose), mySerial(1)
{
  pin_rx = rx;
  pin_tx = tx;

  mySerial.begin(MHZ19_BAUDRATE, SERIAL_8N1, pin_rx, pin_tx); // (ESP32 Example) device to MH-Z19 serial start
  myMHZ19.begin(mySerial);                                    // *Serial(Stream) reference must be passed to library begin().

  // calibration
  // manually
  // MH-Z19 works best in this range up to 2000, as commented in MHZ19.h
  myMHZ19.setRange(2000);
  myMHZ19.autoCalibration(true);
}

int TM_MH_Z19_Class::read_values()
{
  // data[0] = myMHZ19.getCO2();
  // data[1] = myMHZ19.getTemperature(false);
  // temperature is not reliable, as it returns 42°C for room temperature
  data = myMHZ19.getCO2();

  if (verbose)
  {
    TM_Device_Class::printDeviceName();
    Serial.print("CO2 = ");
    Serial.print(data);
    Serial.println(" ppm");
    // TM_Device_Class::printDeviceName();
    // Serial.print("T = ");
    // Serial.print(data[1]);
    // Serial.println(" C");
  }
  // return (float *)&data; // return array of floats
  return data; // CO2 as int
}