esphome-docs/components/sensor/template.rst
Chris Nussbaum 1d253f135e
Template sensor publish updates (#1444)
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
2021-09-08 15:36:57 +12:00

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Template Sensor
===============
.. seo::
:description: Instructions for setting up template sensors with ESPHome.
:image: description.png
The ``template`` sensor platform allows you to create a sensor with templated values
using :ref:`lambdas <config-lambda>`.
.. code-block:: yaml
# Example configuration entry
sensor:
- platform: template
name: "Template Sensor"
lambda: |-
if (id(some_binary_sensor).state) {
return 42.0;
} else {
return 0.0;
}
update_interval: 60s
Possible return values for the lambda:
- ``return <FLOATING_POINT_NUMBER>;`` the new value for the sensor.
- ``return NAN;`` if the state should be considered invalid to indicate an error (advanced).
- ``return {};`` if you don't want to publish a new state (advanced).
Configuration variables:
------------------------
- **name** (**Required**, string): The name of the sensor.
- **lambda** (*Optional*, :ref:`lambda <config-lambda>`):
Lambda to be evaluated every update interval to get the new value of the sensor
- **update_interval** (*Optional*, :ref:`config-time`): The interval to publish the value of the
sensor, either the result of the lambda function or if no lambda function the last value
published using the publish action. Defaults to ``60s``.
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
- All other options from :ref:`Sensor <config-sensor>`.
.. _sensor-template-publish_action:
``sensor.template.publish`` Action
----------------------------------
You can also publish a state to a template sensor from elsewhere in your YAML file
with the ``sensor.template.publish`` action.
.. code-block:: yaml
# Example configuration entry
sensor:
- platform: template
name: "Template Sensor"
id: template_sens
# in some trigger
on_...:
- sensor.template.publish:
id: template_sens
state: 42.0
# Templated
- sensor.template.publish:
id: template_sens
state: !lambda 'return 42.0;'
Configuration options:
- **id** (**Required**, :ref:`config-id`): The ID of the template sensor.
- **state** (**Required**, float, :ref:`templatable <config-templatable>`):
The state to publish.
.. note::
This action can also be written in lambdas:
.. code-block:: cpp
id(template_sens).publish_state(42.0);
See Also
--------
- :ref:`sensor-filters`
- :ref:`automation`
- :apiref:`template/sensor/template_sensor.h`
- :ghedit:`Edit`