core/homeassistant/components/sensor/onewire.py

103 lines
3.1 KiB
Python

"""
homeassistant.components.sensor.onewire
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Support for DS18B20 One Wire Sensors.
For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/sensor.onewire/
"""
from glob import glob
import logging
import os
import time
from homeassistant.const import TEMP_CELCIUS, STATE_UNKNOWN
from homeassistant.helpers.entity import Entity
BASE_DIR = '/sys/bus/w1/devices/'
DEVICE_FOLDERS = glob(os.path.join(BASE_DIR, '28*'))
SENSOR_IDS = []
DEVICE_FILES = []
for device_folder in DEVICE_FOLDERS:
SENSOR_IDS.append(os.path.split(device_folder)[1])
DEVICE_FILES.append(os.path.join(device_folder, 'w1_slave'))
_LOGGER = logging.getLogger(__name__)
# pylint: disable=unused-argument
def setup_platform(hass, config, add_devices, discovery_info=None):
""" Sets up the one wire Sensors. """
if DEVICE_FILES == []:
_LOGGER.error('No onewire sensor found.')
_LOGGER.error('Check if dtoverlay=w1-gpio,gpiopin=4.')
_LOGGER.error('is in your /boot/config.txt and')
_LOGGER.error('the correct gpiopin number is set.')
return
devs = []
names = SENSOR_IDS
for key in config.keys():
if key == "names":
# only one name given
if isinstance(config['names'], str):
names = [config['names']]
# map names and sensors in given order
elif isinstance(config['names'], list):
names = config['names']
# map names to ids.
elif isinstance(config['names'], dict):
names = []
for sensor_id in SENSOR_IDS:
names.append(config['names'].get(sensor_id, sensor_id))
for device_file, name in zip(DEVICE_FILES, names):
devs.append(OneWire(name, device_file))
add_devices(devs)
class OneWire(Entity):
""" An One wire Sensor. """
def __init__(self, name, device_file):
self._name = name
self._device_file = device_file
self._state = STATE_UNKNOWN
self.update()
def _read_temp_raw(self):
""" Read the temperature as it is returned by the sensor. """
ds_device_file = open(self._device_file, 'r')
lines = ds_device_file.readlines()
ds_device_file.close()
return lines
@property
def name(self):
""" The name of the sensor. """
return self._name
@property
def state(self):
""" Returns the state of the device. """
return self._state
@property
def unit_of_measurement(self):
""" Unit the value is expressed in. """
return TEMP_CELCIUS
def update(self):
""" Gets the latest data from the device. """
lines = self._read_temp_raw()
while lines[0].strip()[-3:] != 'YES':
time.sleep(0.2)
lines = self._read_temp_raw()
equals_pos = lines[1].find('t=')
if equals_pos != -1:
temp_string = lines[1][equals_pos+2:]
temp = round(float(temp_string) / 1000.0, 1)
if temp < -55 or temp > 125:
return
self._state = temp