Add documentation on the manual_mqtt alarm (#2921)

source/_components/alarm_control_panel.manual_mqtt.markdown

@@ -0,0 +1,80 @@
+---
+layout: page
+title: "Manual Alarm Control Panel with MQTT Support"
+description: "Instructions how to integrate manual alarms into Home Assistant with MQTT support."
+date: 2017-07-02 9:10
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: home-assistant.png
+ha_category: Alarm
+ha_release: 0.49
+---
+
+This component extends the [manual alarm](/components/alarm_control_panel.manual/) by adding support for MQTT control of the alarm by a remote device.  It can be used to create external keypads which simply change the state of the manual alarm in Home Assistant.
+
+It's essentially the opposite of the [MQTT Alarm Panel](/components/alarm_control_panel.mqtt/) which allows Home Assistant to observe an existing, fully-featured alarm where all of the alarm logic is embedded in that physical device.
+
+The component will accept the following commands from your Alarm Panel via the `command_topic`:
+
+- `DISARM`
+- `ARM_HOME`
+- `ARM_AWAY`
+
+When the state of the manual alarm changes, Home Assistant will publish one of the following states to the `state_topic`:
+
+- 'disarmed'
+- 'armed_home'
+- 'armed_away'
+- 'pending'
+- 'triggered'
+
+```yaml
+# Example configuration.yaml entry
+alarm_control_panel:
+  - platform: manual_mqtt
+    state_topic: home/alarm
+    command_topic: home/alarm/set
+```
+
+Configuration variables:
+
+All configuration variables from the base manual alarm platform are available:
+
+- **name** (*Optional*): The name of the alarm. Default is "HA Alarm".
+- **code** (*Optional*): If defined, specifies a code to enable or disable the alarm in the frontend. This code is not required for MQTT interactions.
+- **pending_time** (*Optional*): The time in seconds of the pending time before arming the alarm. Default is 60 seconds.
+- **trigger_time** (*Optional*): The time in seconds of the trigger time in which the alarm is firing. Default is 120 seconds.
+- **disarm_after_trigger** (*Optional*): If true, the alarm will automatically disarm after it has been triggered instead of returning to the previous state.
+
+Additionally, the following MQTT configuration variables are also available:
+
+- **state_topic** (*Required*): The MQTT topic HA will publish state updates to.
+- **command_topic** (*Required*): The MQTT topic HA will subscribe to to receive commands from a remote device to change the alarm state.
+- **qos** (*Optional*): The maximum QoS level for subscribing and publishing to MQTT messages. Default is 0.
+- **payload_disarm** (*Optional*): The payload to disarm this Alarm Panel. Default is "DISARM".
+- **payload_arm_home** (*Optional*): The payload to set armed-home mode on this Alarm Panel. Default is "ARM_HOME".
+- **payload_arm_away** (*Optional*): The payload to set armed-away mode on this Alarm Panel. Default is "ARM_AWAY".
+
+## {% linkable_title Examples %}
+
+Refer to the [Manual Alarm Control page](/components/alarm_control_panel.manual/#examples) for some real life examples of how to use this panel.
+
+## {% linkable_title MQTT Control %}
+
+The state of this alarm can be controlled using [MQTT](/components/mqtt/).  Ensure you've configured that before adding this component.
+
+To change the state of the alarm, publish one of the following messages to the `command_topic`:
+
+ - `DISARM`
+ - `ARM_HOME`
+ - `ARM_AWAY`
+
+To receive state updates from HA, subscribe to the `state_topic`.  HA will publish a new message whenever the state changes:
+
+ - `disarmed`
+ - `armed_home`
+ - `armed_away`
+ - `pending`
+ - `triggered`