Added a simple_alarm component

README.md

@@ -226,6 +226,15 @@ Registers service `browser/browse_url` that opens `url` as specified in event_da
 **tellstick_sensor**
 Shows the values of that sensors that is connected to your Tellstick.
 
+**simple_alarm**
+Will provide simple alarm functionality. Will flash a light shortly if a known device comes home. Will flash the lights red if the lights turn on while no one is home.
+
+Depends on device_tracker, light.
+
+Config options:
+known_light: entity id of the light/light group to target to flash when a known device comes home
+unknown_light: entity if of the light/light group to target when a light is turned on while no one is at home.
+
 <a name='API'></a>
 ## Rest API
 

config/home-assistant.conf.example

@@ -53,6 +53,12 @@ xbmc=XBMC.App
 
 [example]
 
+[simple_alarm]
+# Which light/light group has to flash when a known device comes home
+known_light=light.Bowl
+# Which light/light group has to flash red when light turns on while no one home
+unknown_light=group.living_room
+
 [browser]
 
 [keyboard]

homeassistant/components/simple_alarm.py

@@ -0,0 +1,95 @@
+"""
+homeassistant.components.simple_alarm
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Provides a simple alarm feature:
+ - flash a light when a known device comes home
+ - flash a light red if a light turns on while there is no one home.
+"""
+import logging
+
+import homeassistant.loader as loader
+from homeassistant.const import STATE_ON, STATE_OFF, STATE_HOME, STATE_NOT_HOME
+
+DOMAIN = "simple_alarm"
+
+DEPENDENCIES = ['group', 'device_tracker', 'light']
+
+# Attribute to tell which light has to flash whem a known person comes home
+# If ommitted will flash all.
+CONF_KNOWN_LIGHT = "known_light"
+
+# Attribute to tell which light has to flash whem an unknown person comes home
+# If ommitted will flash all.
+CONF_UNKNOWN_LIGHT = "unknown_light"
+
+# Services to test the alarms
+SERVICE_TEST_KNOWN_ALARM = "test_known"
+SERVICE_TEST_UNKNOWN_ALARM = "test_unknown"
+
+
+def setup(hass, config):
+    """ Sets up the simple alarms. """
+    logger = logging.getLogger(__name__)
+
+    device_tracker = loader.get_component('device_tracker')
+    light = loader.get_component('light')
+
+    light_ids = []
+
+    for conf_key in (CONF_KNOWN_LIGHT, CONF_UNKNOWN_LIGHT):
+        light_id = config[DOMAIN].get(conf_key) or light.ENTITY_ID_ALL_LIGHTS
+
+        if hass.states.get(light_id) is None:
+            logger.error(
+                'Light id %s could not be found in state machine', light_id)
+
+            return False
+
+        else:
+            light_ids.append(light_id)
+
+    # pylint: disable=unbalanced-tuple-unpacking
+    known_light_id, unknown_light_id = light_ids
+
+    if hass.states.get(device_tracker.ENTITY_ID_ALL_DEVICES) is None:
+        logger.error('No devices are being tracked, cannot setup alarm')
+
+        return False
+
+    def known_alarm():
+        """ Fire an alarm if a known person arrives home. """
+        light.turn_on(hass, known_light_id, flash=light.FLASH_SHORT)
+
+    def unknown_alarm():
+        """ Fire an alarm if the light turns on while no one is home. """
+        light.turn_on(
+            hass, unknown_light_id,
+            flash=light.FLASH_LONG, rgb_color=[255, 0, 0])
+
+    # Setup services to test the effect
+    hass.services.register(
+        DOMAIN, SERVICE_TEST_KNOWN_ALARM, lambda call: known_alarm())
+    hass.services.register(
+        DOMAIN, SERVICE_TEST_UNKNOWN_ALARM, lambda call: unknown_alarm())
+
+    # pylint: disable=unused-argument
+    def unknown_alarm_if_lights_on(entity_id, old_state, new_state):
+        """ Called when a light has been turned on. """
+        if not device_tracker.is_on(hass):
+            unknown_alarm()
+
+    hass.states.track_change(
+        light.ENTITY_ID_ALL_LIGHTS,
+        unknown_alarm_if_lights_on, STATE_OFF, STATE_ON)
+
+    # Not defined as a lambda so the __repr__ has a nice name.
+    # pylint: disable=unused-argument
+    def ring_known_alarm(entity_id, old_state, new_state):
+        """ Called when a known person comes home. """
+        known_alarm()
+
+    # Track home coming of each device
+    hass.states.track_change(
+        hass.states.entity_ids(device_tracker.DOMAIN),
+        ring_known_alarm, STATE_NOT_HOME, STATE_HOME)