diff --git a/homeassistant/components/alexa.py b/homeassistant/components/alexa.py
index 3a41d51419b..969c20583ee 100644
--- a/homeassistant/components/alexa.py
+++ b/homeassistant/components/alexa.py
@@ -11,17 +11,17 @@ from homeassistant.const import HTTP_BAD_REQUEST
 from homeassistant.helpers import template, script
 from homeassistant.components.http import HomeAssistantView
 
-DOMAIN = 'alexa'
-DEPENDENCIES = ['http']
-
 _LOGGER = logging.getLogger(__name__)
 
 API_ENDPOINT = '/api/alexa'
 
-CONF_INTENTS = 'intents'
-CONF_CARD = 'card'
-CONF_SPEECH = 'speech'
 CONF_ACTION = 'action'
+CONF_CARD = 'card'
+CONF_INTENTS = 'intents'
+CONF_SPEECH = 'speech'
+
+DOMAIN = 'alexa'
+DEPENDENCIES = ['http']
 
 
 def setup(hass, config):
diff --git a/homeassistant/components/arduino.py b/homeassistant/components/arduino.py
index 85431eb2753..73bd7a51dad 100644
--- a/homeassistant/components/arduino.py
+++ b/homeassistant/components/arduino.py
@@ -25,7 +25,7 @@ CONFIG_SCHEMA = vol.Schema({
     DOMAIN: vol.Schema({
         vol.Required(CONF_PORT): cv.string,
     }),
-})
+}, extra=vol.ALLOW_EXTRA)
 
 
 def setup(hass, config):
diff --git a/homeassistant/components/configurator.py b/homeassistant/components/configurator.py
index b7c102a584c..9f5cb397587 100644
--- a/homeassistant/components/configurator.py
+++ b/homeassistant/components/configurator.py
@@ -11,26 +11,26 @@ import logging
 from homeassistant.const import EVENT_TIME_CHANGED, ATTR_FRIENDLY_NAME
 from homeassistant.helpers.entity import generate_entity_id
 
-DOMAIN = "configurator"
-ENTITY_ID_FORMAT = DOMAIN + ".{}"
-
-SERVICE_CONFIGURE = "configure"
-
-STATE_CONFIGURE = "configure"
-STATE_CONFIGURED = "configured"
-
-ATTR_LINK_NAME = "link_name"
-ATTR_LINK_URL = "link_url"
-ATTR_CONFIGURE_ID = "configure_id"
-ATTR_DESCRIPTION = "description"
-ATTR_DESCRIPTION_IMAGE = "description_image"
-ATTR_SUBMIT_CAPTION = "submit_caption"
-ATTR_FIELDS = "fields"
-ATTR_ERRORS = "errors"
-
-_REQUESTS = {}
 _INSTANCES = {}
 _LOGGER = logging.getLogger(__name__)
+_REQUESTS = {}
+
+ATTR_CONFIGURE_ID = 'configure_id'
+ATTR_DESCRIPTION = 'description'
+ATTR_DESCRIPTION_IMAGE = 'description_image'
+ATTR_ERRORS = 'errors'
+ATTR_FIELDS = 'fields'
+ATTR_LINK_NAME = 'link_name'
+ATTR_LINK_URL = 'link_url'
+ATTR_SUBMIT_CAPTION = 'submit_caption'
+
+DOMAIN = 'configurator'
+
+ENTITY_ID_FORMAT = DOMAIN + '.{}'
+
+SERVICE_CONFIGURE = 'configure'
+STATE_CONFIGURE = 'configure'
+STATE_CONFIGURED = 'configured'
 
 
 # pylint: disable=too-many-arguments
diff --git a/homeassistant/components/conversation.py b/homeassistant/components/conversation.py
index 6b580fa21fb..89cbd73b6ab 100644
--- a/homeassistant/components/conversation.py
+++ b/homeassistant/components/conversation.py
@@ -15,20 +15,20 @@ from homeassistant.const import (
     ATTR_ENTITY_ID, SERVICE_TURN_OFF, SERVICE_TURN_ON)
 import homeassistant.helpers.config_validation as cv
 
-DOMAIN = "conversation"
+REQUIREMENTS = ['fuzzywuzzy==0.11.1']
 
-SERVICE_PROCESS = "process"
+ATTR_TEXT = 'text'
 
-ATTR_TEXT = "text"
+DOMAIN = 'conversation'
+
+REGEX_TURN_COMMAND = re.compile(r'turn (?P<name>(?: |\w)+) (?P<command>\w+)')
+
+SERVICE_PROCESS = 'process'
 
 SERVICE_PROCESS_SCHEMA = vol.Schema({
     vol.Required(ATTR_TEXT): vol.All(cv.string, vol.Lower),
 })
 
-REGEX_TURN_COMMAND = re.compile(r'turn (?P<name>(?: |\w)+) (?P<command>\w+)')
-
-REQUIREMENTS = ['fuzzywuzzy==0.11.1']
-
 
 def setup(hass, config):
     """Register the process service."""
diff --git a/homeassistant/components/demo.py b/homeassistant/components/demo.py
index 863a2084892..5695bc5005a 100644
--- a/homeassistant/components/demo.py
+++ b/homeassistant/components/demo.py
@@ -11,9 +11,8 @@ import homeassistant.core as ha
 import homeassistant.loader as loader
 from homeassistant.const import ATTR_ENTITY_ID, CONF_PLATFORM
 
-DOMAIN = "demo"
-
 DEPENDENCIES = ['conversation', 'introduction', 'zone']
+DOMAIN = 'demo'
 
 COMPONENTS_WITH_DEMO_PLATFORM = [
     'alarm_control_panel',
diff --git a/homeassistant/components/discovery.py b/homeassistant/components/discovery.py
index 6db4af66207..0ac40c00f90 100644
--- a/homeassistant/components/discovery.py
+++ b/homeassistant/components/discovery.py
@@ -12,13 +12,13 @@ import threading
 from homeassistant.const import EVENT_HOMEASSISTANT_START
 from homeassistant.helpers.discovery import load_platform, discover
 
-DOMAIN = "discovery"
 REQUIREMENTS = ['netdisco==0.7.1']
 
-SCAN_INTERVAL = 300  # seconds
+DOMAIN = 'discovery'
 
-SERVICE_WEMO = 'belkin_wemo'
+SCAN_INTERVAL = 300  # seconds
 SERVICE_NETGEAR = 'netgear_router'
+SERVICE_WEMO = 'belkin_wemo'
 
 SERVICE_HANDLERS = {
     SERVICE_NETGEAR: ('device_tracker', None),
diff --git a/homeassistant/components/downloader.py b/homeassistant/components/downloader.py
index c639619d7a7..b752743d2d4 100644
--- a/homeassistant/components/downloader.py
+++ b/homeassistant/components/downloader.py
@@ -16,21 +16,20 @@ from homeassistant.helpers import validate_config
 import homeassistant.helpers.config_validation as cv
 from homeassistant.util import sanitize_filename
 
-DOMAIN = "downloader"
-
-SERVICE_DOWNLOAD_FILE = "download_file"
-
-ATTR_URL = "url"
-ATTR_SUBDIR = "subdir"
-
-SERVICE_DOWNLOAD_FILE_SCHEMA = vol.Schema({
-    # pylint: disable=no-value-for-parameter
-    vol.Required(ATTR_URL): vol.Url(),
-    vol.Optional(ATTR_SUBDIR): cv.string,
-})
+ATTR_SUBDIR = 'subdir'
+ATTR_URL = 'url'
 
 CONF_DOWNLOAD_DIR = 'download_dir'
 
+DOMAIN = 'downloader'
+
+SERVICE_DOWNLOAD_FILE = 'download_file'
+
+SERVICE_DOWNLOAD_FILE_SCHEMA = vol.Schema({
+    vol.Required(ATTR_URL): cv.url,
+    vol.Optional(ATTR_SUBDIR): cv.string,
+})
+
 
 # pylint: disable=too-many-branches
 def setup(hass, config):
diff --git a/homeassistant/components/dweet.py b/homeassistant/components/dweet.py
index 9a17a7aeea3..d56d9d2ef93 100644
--- a/homeassistant/components/dweet.py
+++ b/homeassistant/components/dweet.py
@@ -29,7 +29,7 @@ CONFIG_SCHEMA = vol.Schema({
         vol.Required(CONF_WHITELIST, default=[]):
             vol.All(cv.ensure_list, [cv.entity_id]),
     }),
-})
+}, extra=vol.ALLOW_EXTRA)
 
 
 # pylint: disable=too-many-locals