MH-Z19 CO2 sensor

MH-Z19 CO2 sensor driver. More...

Detailed Description

MH-Z19 CO2 sensor driver.

Description

The MH-Z19 is a CO2 sensor. Measurements are provided in parts per million (ppm) over UART and PWM. The ppm value ranges from 0 (theoretically) to 2000 or 5000, depending on the sensor settings.

In UART mode, additional commands are available to configure the sensor.

Note that the sensor requires considerable time before accurate measurements are provided.

Files
file	mhz19.h
	Interface definition for the MH-Z19 CO2 sensor driver.
file	mhz19_internals.h
	Internal addresses, registers, constants for the MH-Z19 CO2 sensor.
file	mhz19_params.h
	Default configuration for MH-Z19.

Enumerations
enum	{ MHZ19_OK = 0, MHZ19_ERR_INIT = -1, MHZ19_ERR_TIMEOUT = -2, MHZ19_ERR_CHECKSUM = -3 }
	Status and error return codes. More...

Functions
int	mhz19_init (mhz19_t *dev, const mhz19_params_t *params)
	Initialize a MH-Z19 device. More...
int	mhz19_get_ppm (mhz19_t *dev, int16_t *ppm)
	Get measured CO2 ppm value. More...

Variables
const saul_driver_t	mhz19_ppm_saul_driver
	Export SAUL endpoint.

Enumeration Type Documentation

anonymous enum

anonymous enum

Status and error return codes.

Enumerator
MHZ19_OK	everything was fine
MHZ19_ERR_INIT	error initializing the device
MHZ19_ERR_TIMEOUT	timeout on retrieving sensor data
MHZ19_ERR_CHECKSUM	checksum failure on received data

Definition at line 62 of file mhz19.h.

Function Documentation

mhz19_get_ppm()

int mhz19_get_ppm	(	mhz19_t *	dev,
		int16_t *	ppm
	)

Get measured CO2 ppm value.

Parameters

[in]	dev	device descriptor
[out]	ppm	int16_t buffer where CO2 measurement will be written to, in ppm

Returns

MHZ19_OK

MHZ19_ERR_TIMEOUT

MHZ19_ERR_CHECKSUM

mhz19_init()

int mhz19_init	(	mhz19_t *	dev,
		const mhz19_params_t *	params
	)

Initialize a MH-Z19 device.

Parameters

[out]	dev	device descriptor
[in]	params	MH-Z19 initialization struct

Returns

MHZ19_OK

MHZ19_ERR_INIT