home-assistant.io/source/_components/binary_sensor.mqtt.markdown

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layout	title	description	date	sidebar	comments	sharing	footer	logo	ha_category	ha_release	ha_iot_class
page	MQTT Binary Sensor	Instructions how to integrate MQTT binary sensors within Home Assistant.	2015-05-30 23:21	true	false	true	true	mqtt.png	Binary Sensor	0.9	depends

The mqtt binary sensor platform uses an MQTT message payload to set the binary sensor to one of two states: on or off.

The binary sensor state will be updated only after a new message is published on state_topic matching payload_on or payload_off. If these messages are published with the retain flag set, the binary sensor will receive an instant state update after subscription and Home Assistant will display the correct state on startup. Otherwise, the initial state displayed in Home Assistant will be unknown.

The mqtt binary sensor platform optionally supports an availability_topic to receive online and offline messages (birth and LWT messages) from the MQTT device. During normal operation, if the MQTT cover device goes offline (i.e., publishes payload_not_available to availability_topic), Home Assistant will display the binary sensor as unavailable. If these messages are published with the retain flag set, the binary sensor will receive an instant update after subscription and Home Assistant will display the correct availability state of the binary sensor when Home Assistant starts up. If the retain flag is not set, Home Assistant will display the binary sensor as unavailable when Home Assistant starts up. If no availability_topic is defined, Home Assistant will consider the MQTT device to be available.

To use an MQTT binary sensor in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
binary_sensor:
  - platform: mqtt
    state_topic: "home-assistant/window/contact"

{% configuration %} name: description: The name of the binary sensor. required: false type: string default: MQTT Binary Sensor state_topic: description: The MQTT topic subscribed to receive sensor values. required: true type: string payload_on: description: The payload that represents the on state. required: false type: string default: ON payload_off: description: The payload that represents the off state. required: false type: string default: OFF availability_topic: description: "The MQTT topic subscribed to receive birth and LWT messages from the MQTT device. If availability_topic is not defined, the binary sensor availability state will always be available. If availability_topic is defined, the binary sensor availability state will be unavailable by default." required: false type: string payload_available: description: The payload that represents the online state. required: false type: string default: online payload_not_available: description: The payload that represents the offline state. required: false type: string default: offline qos: description: The maximum QoS level to be used when receiving messages. required: false type: integer default: 0 device_class: description: "The type/class of the sensor to set the icon in the frontend." required: false type: string value_template: description: "Defines a template to extract a value from the payload." required: false type: string force_update: description: Sends update events even if the value hasn't changed. Useful if you want to have meaningful value graphs in history. reqired: false type: boolean default: False {% endconfiguration %}

{% linkable_title Examples %}

In this section, you will find some real-life examples of how to use this sensor.

{% linkable_title Full configuration %}

To test, you can use the command line tool mosquitto_pub shipped with mosquitto or the mosquitto-clients package to send MQTT messages. To set the state of the binary sensor manually:

$  mosquitto_pub -h 127.0.0.1 -t home-assistant/window/contact -m "OFF"

The example below shows a full configuration for a binary sensor:

{% raw %}

# Example configuration.yaml entry
binary_sensor:
  - platform: mqtt
    name: "Window Contact Sensor"
    state_topic: "home-assistant/window/contact"
    payload_on: "ON"
    payload_off: "OFF"
    availability_topic: "home-assistant/window/availability"
    payload_available: "online"
    payload_not_available: "offline"
    qos: 0
    device_class: opening
    value_template: '{{ value.x }}'

{% endraw %}

{% linkable_title Get the state of a device with ESPEasy %}

Assuming that you have flashed your ESP8266 unit with ESPEasy. Under "Config" is a name ("Unit Name:") set for your device (here it's "bathroom"). A configuration for a "Controller" for MQTT with the protocol "OpenHAB MQTT" is present and the entries ("Controller Subscribe:" and "Controller Publish:") are adjusted to match your needs. In this example, the topics are prefixed with "home". Also, add a "Switch Input" in the "Devices" tap with the name "switch" and "button" as value.

As soon as the unit is online, you will get the state of the attached button.

home/bathroom/status Connected
...
home/bathroom/switch/button 1

The configuration will look like the example below:

{% raw %}

# Example configuration.yml entry
binary_sensor:
  - platform: mqtt
    name: Bathroom
    state_topic: "home/bathroom/switch/button"
    payload_on: "1"
    payload_off: "0"

{% endraw %}