core/homeassistant/components/sensor/mhz19.py

87 lines
2.4 KiB
Python

"""
Support for CO2 sensor connected to a serial port.
For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/sensor.mhz19/
"""
import logging
import voluptuous as vol
from homeassistant.const import CONF_NAME
from homeassistant.helpers.entity import Entity
import homeassistant.helpers.config_validation as cv
from homeassistant.components.sensor import PLATFORM_SCHEMA
REQUIREMENTS = ['pmsensor==0.3']
_LOGGER = logging.getLogger(__name__)
CONF_SERIAL_DEVICE = 'serial_device'
DEFAULT_NAME = 'CO2 Sensor'
PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
vol.Required(CONF_SERIAL_DEVICE): cv.string,
})
def setup_platform(hass, config, add_devices, discovery_info=None):
"""Setup the available CO2 sensors."""
from pmsensor import co2sensor
try:
co2sensor.read_mh_z19(config.get(CONF_SERIAL_DEVICE))
except OSError as err:
_LOGGER.error("Could not open serial connection to %s (%s)",
config.get(CONF_SERIAL_DEVICE), err)
return False
dev = MHZ19Sensor(config.get(CONF_SERIAL_DEVICE), config.get(CONF_NAME))
add_devices([dev])
class MHZ19Sensor(Entity):
"""Representation of an CO2 sensor."""
def __init__(self, serial_device, name):
"""Initialize a new PM sensor."""
self._name = name
self._state = None
self._serial = serial_device
@property
def name(self):
"""Return the name of the sensor."""
return self._name
@property
def state(self):
"""Return the state of the sensor."""
return self._state
@property
def unit_of_measurement(self):
"""Return the unit of measurement of this entity, if any."""
return "ppm"
def update(self):
"""Read from sensor and update the state."""
from pmsensor import co2sensor
_LOGGER.debug("Reading data from CO2 sensor")
try:
ppm = co2sensor.read_mh_z19(self._serial)
# values from sensor can only between 0 and 5000
if (ppm >= 0) & (ppm <= 5000):
self._state = ppm
except OSError as err:
_LOGGER.error("Could not open serial connection to %s (%s)",
self._serial, err)
return
def should_poll(self):
"""Sensor needs polling."""
return True