Arduino IDE library for the MH-Z16 CO₂ sensor. Tested with ESP32 but might just work for Arduino too.

Version 0.1

By: Intar BV

Based on: https://github.com/nara256/mhz19_uart

License: MIT

1. Add this library to your Arduino IDE's libraries folder.

2. Include the library in your program

3. Connect your MH-Z16 sensor to your ESP32

   MH-Z16 Vcc to 5V power supply
   MH-Z16 GND to common GND
   MH-Z16 Tx to ESP32 GPIO pin to use as Rx
   MH-Z16 Rx to ESP32 GPIO pin to use as Tx
   Other MH-Z16 pins are not supported

4. Upload your program to the ESP32

This library only supports serial UART communication with the MH-Z16.

This library has only been tested on ESP32S.

The isWarming() function does not indicate whether the MH-Z16 is warming up.

Default constructor. You must call begin(int rx, int tx) before you can use the MH-Z16

Constructor that sets Rx and Tx pin, and initialises the serial interface.

Set the Rx and Tx pin, and initialise the serial interface.

Calibrate the zero-point. According to the documentation the MH-Z16 sensor must have been working in a stable gas environment with a CO₂ concentration of 400ppm for 20 minutes before you call this function.

Calibrate the span point. According to the documentation the MH-Z16 sensor must have been working in a stable gas environment with a CO₂ concentration of ppm for 20 minutes before you call this function.

Read the CO₂ concentration in PPM from the sensor. On a read error the return value is -1.

The return value indicates whether the documenation mandated 3 minutes of warm-up time have passed since the call to either MHZ16_uart(int rx, int tx) or begin(int rx, int tx).
Caution: This is not a value read from the MH-Z16

http://www.winsen-sensor.com/d/files/PDF/Infrared%20Gas%20Sensor/NDIR%20CO2%20SENSOR/MH-Z16%20CO2%20V2.1.pdf

First release