DHT support for humidity and temperature offset (#8238)

* Added support for temperature_offset and humidity_offset

Some DHT sensors require some offsets to work.

* Support for temperature and humidity offset

* Changed lines with 79 characters

* Moved const to dht.py from const.py

* Changed temperature_offset range

* Removed the const

const.py is at original state.

* Fixed continuation line under-indented

* Removed first round and added debug info

homeassistant/components/sensor/dht.py

@@ -26,6 +26,8 @@ _LOGGER = logging.getLogger(__name__)
 
 CONF_PIN = 'pin'
 CONF_SENSOR = 'sensor'
+CONF_HUMIDITY_OFFSET = 'humidity_offset'
+CONF_TEMPERATURE_OFFSET = 'temperature_offset'
 
 DEFAULT_NAME = 'DHT Sensor'
 
@@ -45,6 +47,10 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Optional(CONF_MONITORED_CONDITIONS, default=[]):
         vol.All(cv.ensure_list, [vol.In(SENSOR_TYPES)]),
     vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_TEMPERATURE_OFFSET, default=0):
+        vol.All(vol.Coerce(float), vol.Range(min=-100, max=100)),
+    vol.Optional(CONF_HUMIDITY_OFFSET, default=0):
+        vol.All(vol.Coerce(float), vol.Range(min=-100, max=100))
 })
 
 
@@ -61,6 +67,8 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
     }
     sensor = available_sensors.get(config.get(CONF_SENSOR))
     pin = config.get(CONF_PIN)
+    temperature_offset = config.get(CONF_TEMPERATURE_OFFSET)
+    humidity_offset = config.get(CONF_HUMIDITY_OFFSET)
 
     if not sensor:
         _LOGGER.error("DHT sensor type is not supported")
@@ -73,7 +81,8 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
     try:
         for variable in config[CONF_MONITORED_CONDITIONS]:
             dev.append(DHTSensor(
-                data, variable, SENSOR_TYPES[variable][1], name))
+                data, variable, SENSOR_TYPES[variable][1], name,
+                temperature_offset, humidity_offset))
     except KeyError:
         pass
 
@@ -83,13 +92,16 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
 class DHTSensor(Entity):
     """Implementation of the DHT sensor."""
 
-    def __init__(self, dht_client, sensor_type, temp_unit, name):
+    def __init__(self, dht_client, sensor_type, temp_unit, name,
+                 temperature_offset, humidity_offset):
         """Initialize the sensor."""
         self.client_name = name
         self._name = SENSOR_TYPES[sensor_type][0]
         self.dht_client = dht_client
         self.temp_unit = temp_unit
         self.type = sensor_type
+        self.temperature_offset = temperature_offset
+        self.humidity_offset = humidity_offset
         self._state = None
         self._unit_of_measurement = SENSOR_TYPES[sensor_type][1]
         self.update()
@@ -112,18 +124,24 @@ class DHTSensor(Entity):
     def update(self):
         """Get the latest data from the DHT and updates the states."""
         self.dht_client.update()
+        temperature_offset = self.temperature_offset
+        humidity_offset = self.humidity_offset
         data = self.dht_client.data
 
         if self.type == SENSOR_TEMPERATURE:
-            temperature = round(data[SENSOR_TEMPERATURE], 1)
+            temperature = data[SENSOR_TEMPERATURE]
+            _LOGGER.debug("Temperature %.1f \u00b0C + offset %.1f",
+                          temperature, temperature_offset)
             if (temperature >= -20) and (temperature < 80):
-                self._state = temperature
+                self._state = round(temperature + temperature_offset, 1)
                 if self.temp_unit == TEMP_FAHRENHEIT:
                     self._state = round(celsius_to_fahrenheit(temperature), 1)
         elif self.type == SENSOR_HUMIDITY:
-            humidity = round(data[SENSOR_HUMIDITY], 1)
+            humidity = data[SENSOR_HUMIDITY]
+            _LOGGER.debug("Humidity %.1f%% + offset %.1f",
+                          humidity, humidity_offset)
             if (humidity >= 0) and (humidity <= 100):
-                self._state = humidity
+                self._state = round(humidity + humidity_offset, 1)
 
 
 class DHTClient(object):