esphome-docs/components/sensor/template.rst

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Template Sensor
===============
.. seo::
:description: Instructions for setting up template sensors with ESPHome.
:image: description.svg
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:
------------------------
- **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 check the
sensor. Set to ``never`` to disable updates. Defaults to ``60s``.
- 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`