diff --git a/homeassistant/components/alarm_control_panel/mqtt.py b/homeassistant/components/alarm_control_panel/mqtt.py
index 3bc7b860869..b5bdf478add 100644
--- a/homeassistant/components/alarm_control_panel/mqtt.py
+++ b/homeassistant/components/alarm_control_panel/mqtt.py
@@ -13,33 +13,31 @@ import homeassistant.components.mqtt as mqtt
 from homeassistant.const import (
     STATE_ALARM_ARMED_AWAY, STATE_ALARM_ARMED_HOME, STATE_ALARM_DISARMED,
     STATE_ALARM_PENDING, STATE_ALARM_TRIGGERED, STATE_UNKNOWN,
-    CONF_NAME)
+    CONF_NAME, CONF_CODE)
 from homeassistant.components.mqtt import (
     CONF_STATE_TOPIC, CONF_COMMAND_TOPIC, CONF_QOS)
 import homeassistant.helpers.config_validation as cv
 
 _LOGGER = logging.getLogger(__name__)
 
-DEPENDENCIES = ['mqtt']
-
 CONF_PAYLOAD_DISARM = 'payload_disarm'
 CONF_PAYLOAD_ARM_HOME = 'payload_arm_home'
 CONF_PAYLOAD_ARM_AWAY = 'payload_arm_away'
-CONF_CODE = 'code'
 
-DEFAULT_NAME = "MQTT Alarm"
-DEFAULT_DISARM = "DISARM"
-DEFAULT_ARM_HOME = "ARM_HOME"
-DEFAULT_ARM_AWAY = "ARM_AWAY"
+DEFAULT_ARM_AWAY = 'ARM_AWAY'
+DEFAULT_ARM_HOME = 'ARM_HOME'
+DEFAULT_DISARM = 'DISARM'
+DEFAULT_NAME = 'MQTT Alarm'
+DEPENDENCIES = ['mqtt']
 
 PLATFORM_SCHEMA = mqtt.MQTT_BASE_PLATFORM_SCHEMA.extend({
-    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
-    vol.Required(CONF_STATE_TOPIC): mqtt.valid_subscribe_topic,
     vol.Required(CONF_COMMAND_TOPIC): mqtt.valid_publish_topic,
-    vol.Optional(CONF_PAYLOAD_DISARM, default=DEFAULT_DISARM): cv.string,
-    vol.Optional(CONF_PAYLOAD_ARM_HOME, default=DEFAULT_ARM_HOME): cv.string,
-    vol.Optional(CONF_PAYLOAD_ARM_AWAY, default=DEFAULT_ARM_AWAY): cv.string,
+    vol.Required(CONF_STATE_TOPIC): mqtt.valid_subscribe_topic,
     vol.Optional(CONF_CODE): cv.string,
+    vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_PAYLOAD_ARM_AWAY, default=DEFAULT_ARM_AWAY): cv.string,
+    vol.Optional(CONF_PAYLOAD_ARM_HOME, default=DEFAULT_ARM_HOME): cv.string,
+    vol.Optional(CONF_PAYLOAD_DISARM, default=DEFAULT_DISARM): cv.string,
 })
 
 
@@ -47,20 +45,20 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
     """Setup the MQTT platform."""
     add_devices([MqttAlarm(
         hass,
-        config[CONF_NAME],
-        config[CONF_STATE_TOPIC],
-        config[CONF_COMMAND_TOPIC],
-        config[CONF_QOS],
-        config[CONF_PAYLOAD_DISARM],
-        config[CONF_PAYLOAD_ARM_HOME],
-        config[CONF_PAYLOAD_ARM_AWAY],
+        config.get(CONF_NAME),
+        config.get(CONF_STATE_TOPIC),
+        config.get(CONF_COMMAND_TOPIC),
+        config.get(CONF_QOS),
+        config.get(CONF_PAYLOAD_DISARM),
+        config.get(CONF_PAYLOAD_ARM_HOME),
+        config.get(CONF_PAYLOAD_ARM_AWAY),
         config.get(CONF_CODE))])
 
 
 # pylint: disable=too-many-arguments, too-many-instance-attributes
 # pylint: disable=abstract-method
 class MqttAlarm(alarm.AlarmControlPanel):
-    """Represent a MQTT alarm status."""
+    """Representation of a MQTT alarm status."""
 
     def __init__(self, hass, name, state_topic, command_topic, qos,
                  payload_disarm, payload_arm_home, payload_arm_away, code):
diff --git a/homeassistant/components/automation/mqtt.py b/homeassistant/components/automation/mqtt.py
index 5cd60ff0cea..6824c32bf07 100644
--- a/homeassistant/components/automation/mqtt.py
+++ b/homeassistant/components/automation/mqtt.py
@@ -7,13 +7,12 @@ at https://home-assistant.io/components/automation/#mqtt-trigger
 import voluptuous as vol
 
 import homeassistant.components.mqtt as mqtt
-from homeassistant.const import CONF_PLATFORM
+from homeassistant.const import (CONF_PLATFORM, CONF_PAYLOAD)
 import homeassistant.helpers.config_validation as cv
 
 DEPENDENCIES = ['mqtt']
 
 CONF_TOPIC = 'topic'
-CONF_PAYLOAD = 'payload'
 
 TRIGGER_SCHEMA = vol.Schema({
     vol.Required(CONF_PLATFORM): mqtt.DOMAIN,
@@ -24,7 +23,7 @@ TRIGGER_SCHEMA = vol.Schema({
 
 def trigger(hass, config, action):
     """Listen for state changes based on configuration."""
-    topic = config[CONF_TOPIC]
+    topic = config.get(CONF_TOPIC)
     payload = config.get(CONF_PAYLOAD)
 
     def mqtt_automation_listener(msg_topic, msg_payload, qos):
diff --git a/homeassistant/components/binary_sensor/mqtt.py b/homeassistant/components/binary_sensor/mqtt.py
index a381305691a..fd767bb1528 100644
--- a/homeassistant/components/binary_sensor/mqtt.py
+++ b/homeassistant/components/binary_sensor/mqtt.py
@@ -9,45 +9,42 @@ import logging
 import voluptuous as vol
 
 import homeassistant.components.mqtt as mqtt
-from homeassistant.components.binary_sensor import (BinarySensorDevice,
-                                                    SENSOR_CLASSES)
-from homeassistant.const import CONF_NAME, CONF_VALUE_TEMPLATE
-from homeassistant.components.mqtt import CONF_STATE_TOPIC, CONF_QOS
+from homeassistant.components.binary_sensor import (
+    BinarySensorDevice, SENSOR_CLASSES)
+from homeassistant.const import (
+    CONF_NAME, CONF_VALUE_TEMPLATE, CONF_PAYLOAD_ON, CONF_PAYLOAD_OFF,
+    CONF_SENSOR_CLASS)
+from homeassistant.components.mqtt import (CONF_STATE_TOPIC, CONF_QOS)
 from homeassistant.helpers import template
 import homeassistant.helpers.config_validation as cv
 
 _LOGGER = logging.getLogger(__name__)
 
-DEPENDENCIES = ['mqtt']
-
-CONF_SENSOR_CLASS = 'sensor_class'
-CONF_PAYLOAD_ON = 'payload_on'
-CONF_PAYLOAD_OFF = 'payload_off'
-
 DEFAULT_NAME = 'MQTT Binary sensor'
-DEFAULT_PAYLOAD_ON = 'ON'
 DEFAULT_PAYLOAD_OFF = 'OFF'
+DEFAULT_PAYLOAD_ON = 'ON'
+DEPENDENCIES = ['mqtt']
 
 PLATFORM_SCHEMA = mqtt.MQTT_RO_PLATFORM_SCHEMA.extend({
     vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
+    vol.Optional(CONF_PAYLOAD_OFF, default=DEFAULT_PAYLOAD_OFF): cv.string,
+    vol.Optional(CONF_PAYLOAD_ON, default=DEFAULT_PAYLOAD_ON): cv.string,
     vol.Optional(CONF_SENSOR_CLASS, default=None):
         vol.Any(vol.In(SENSOR_CLASSES), vol.SetTo(None)),
-    vol.Optional(CONF_PAYLOAD_ON, default=DEFAULT_PAYLOAD_ON): cv.string,
-    vol.Optional(CONF_PAYLOAD_OFF, default=DEFAULT_PAYLOAD_OFF): cv.string,
 })
 
 
 # pylint: disable=unused-argument
 def setup_platform(hass, config, add_devices, discovery_info=None):
-    """Add MQTT binary sensor."""
+    """Setup the MQTT binary sensor."""
     add_devices([MqttBinarySensor(
         hass,
-        config[CONF_NAME],
-        config[CONF_STATE_TOPIC],
-        config[CONF_SENSOR_CLASS],
-        config[CONF_QOS],
-        config[CONF_PAYLOAD_ON],
-        config[CONF_PAYLOAD_OFF],
+        config.get(CONF_NAME),
+        config.get(CONF_STATE_TOPIC),
+        config.get(CONF_SENSOR_CLASS),
+        config.get(CONF_QOS),
+        config.get(CONF_PAYLOAD_ON),
+        config.get(CONF_PAYLOAD_OFF),
         config.get(CONF_VALUE_TEMPLATE)
     )])