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

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layout	title	description	date	sidebar	comments	sharing	footer	ha_category	logo	ha_release	ha_iot_class
page	Trend Binary Sensor	Instructions on how to integrate Trend binary sensors into Home Assistant.	2016-09-05 10:00	true	false	true	true	Binary Sensor	home-assistant.png	0.28	Local Push

The trend platform allows you to create sensors which show the trend of numeric state orstate_attributes from other entities. This sensor requires at least two updates of the underlying sensor to establish a trend. Thus it can take some time to show an accurate state. It can be useful as part of automations, where you want to base an action on a trend.

To enable Trend binary sensors in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
binary_sensor:
  - platform: trend
    sensors:
      solar_angle:
        entity_id: sensor.cpu_speed

Configuration variables:

• sensors array (Required): List of your sensors.
  • entity_id (Required): The entity that this sensor tracks.
  • attribute (Optional): The attribute of the entity that this sensor tracks. If no attribute is specified then the sensor will track the state.
  • device_class (Optional): The type/class of the sensor to set the icon in the frontend.
  • friendly_name (Optional): Name to use in the Frontend.
  • invert (Optional): Invert the result (so true means descending rather than ascending). Defaults to False
  • max_samples (Optional): Limit the maximum number of stored samples. Defaults to 2.
  • min_gradient (Optional): The minimum rate at which the observed value must be changing for this sensor to switch on. Defaults to 0.0
  • sample_duration (Optional): The duration in seconds to store samples for. Samples older than this value will be discarded. Defaults to 0

{% linkable_title Using Multiple Samples %}

If the optional sample_duration and max_samples parameters are specified then multiple samples can be stored and used to detect long-term trends.

Each time the state changes, a new sample is stored along with the sample time. Samples older than sample_duration seconds will be discarded.

A trend line is then fitted to the available samples, and the gradient of this line is compared to min_gradient to determine the state of the trend sensor. The gradient is measured in sensor units per second - so if you want to know when the temperature is falling by 2 degrees per hour, use a gradient of (-2) / (60 x 60) = -0.00055

The current number of stored samples is displayed on the States page.

{% linkable_title Examples %}

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

This example indicates true if the sun is still rising:

binary_sensor:
  - platform: trend
    sensors:
      sun_rising:
        entity_id: sensor.cpu_speed

This example creates two sensors to indicate whether the temperature is rising or falling at a rate of at least 3 degrees an hour, and collects samples over a two hour period:

binary_sensor:
  - platform: trend
    sensors:
      temp_falling:
        entity_id: sensor.outside_temperature
        sample_duration: 7200
        min_gradient: -0.0008
        device_class: cold

      temp_rising:
        entity_id: sensor.outside_temperature
        sample_duration: 7200
        min_gradient: 0.0008
        device_class: heat