MH-Z19B CO2 sensor library for Arduino. More...

#include <Arduino.h>

Include dependency graph for ErriezMHZ19B.h:

This graph shows which files directly or indirectly include this file:

Classes
class	ErriezMHZ19B
	Class ErriezMHZ19B. More...

Macros
#define	MHZ19B_WARMING_UP_TIME_MS (3UL * 60000UL)
	3 minutes warming-up time after power-on before valid data returned More...

#define	MHZ19B_READ_INTERVAL_MS (5UL * 1000UL)
	Minimum response time between CO2 reads (EXPERIMENTALLY DEFINED)

#define	MHZ19B_SERIAL_RX_BYTES 9
	Fixed 9 Bytes response.

#define	MHZ19B_SERIAL_RX_TIMEOUT_MS 120
	Response timeout between 15..120 ms at 9600 baud works reliable for all commands.

#define	MHZ19B_CMD_SET_AUTO_CAL 0x79
	Command set auto calibration on/off.

#define	MHZ19B_CMD_READ_CO2 0x86
	Command read CO2 concentration.

#define	MHZ19B_CMD_CAL_ZERO_POINT 0x87
	Command calibrate zero point at 400ppm.

#define	MHZ19B_CMD_CAL_SPAN_POINT 0x88
	Command calibrate span point (NOT IMPLEMENTED)

#define	MHZ19B_CMD_SET_RANGE 0x99
	Command set detection range.

#define	MHZ19B_CMD_GET_AUTO_CAL 0x7D
	Command get auto calibration status (NOT DOCUMENTED)

#define	MHZ19B_CMD_GET_RANGE 0x9B
	Command get range detection (NOT DOCUMENTED)

#define	MHZ19B_CMD_GET_VERSION 0xA0
	Command get firmware version (NOT DOCUMENTED)

Enumerations
enum	MHZ19B_Result_e { MHZ19B_RESULT_OK = 0 , MHZ19B_RESULT_ERROR = -1 , MHZ19B_RESULT_ERR_CRC = -2 , MHZ19B_RESULT_ERR_TIMEOUT = -3 , MHZ19B_RESULT_ARGUMENT_ERROR = -4 }
	Response on a command. More...

enum	MHZ19B_Range_e { MHZ19B_RANGE_2000 = 2000 , MHZ19B_RANGE_5000 = 5000 }
	PPM range. More...

Detailed Description

MH-Z19B CO2 sensor library for Arduino.

Source: https://github.com/Erriez/ErriezMHZ19B Documentation: https://erriez.github.io/ErriezMHZ19B

Definition in file ErriezMHZ19B.h.

Macro Definition Documentation

◆ MHZ19B_WARMING_UP_TIME_MS

#define MHZ19B_WARMING_UP_TIME_MS (3UL * 60000UL)

3 minutes warming-up time after power-on before valid data returned

Enable smart warming-up to return false when CO2 value changes within 3 minutes pre-heating time. Can be used when MCU is reset and sensor powered-up for >3 minutes. Recommended to disable for deployment to ensure warming-up timing.

Definition at line 45 of file ErriezMHZ19B.h.

Enumeration Type Documentation

◆ MHZ19B_Range_e

enum MHZ19B_Range_e

PPM range.

Enumerator
MHZ19B_RANGE_2000	Range 2000 ppm.
MHZ19B_RANGE_5000	Range 5000 ppm (Default)

Definition at line 82 of file ErriezMHZ19B.h.

◆ MHZ19B_Result_e

enum MHZ19B_Result_e

Response on a command.

Enumerator
MHZ19B_RESULT_OK	Response OK.
MHZ19B_RESULT_ERROR	Response error.
MHZ19B_RESULT_ERR_CRC	Response CRC error.
MHZ19B_RESULT_ERR_TIMEOUT	Response timeout.
MHZ19B_RESULT_ARGUMENT_ERROR	Response argument error.

Definition at line 71 of file ErriezMHZ19B.h.

Classes