esphome-docs/esphomeyaml/components/sensor/adc.rst

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Analog To Digital Sensor
========================
The Analog To Digital (``adc``) Sensor allows you to use the built-in
ADC in your device to measure a voltage on certain pins. On the ESP8266
only pin A0 (GPIO17) supports this. On the ESP32 pins GPIO32 through
GPIO39 can be used.
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.. figure:: images/adc-ui.png
:align: center
:width: 80.0%
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.. code:: yaml
# Example configuration entry
sensor:
- platform: adc
pin: A0
name: "Living Room Brightness"
update_interval: 15s
Configuration variables:
~~~~~~~~~~~~~~~~~~~~~~~~
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- **pin** (**Required**, :ref:`config-pin`): The pin to measure the voltage on.
- **name** (**Required**, string): The name of the voltage sensor.
- **attenuation** (*Optional*): Only on ESP32. Specify the ADC
attenuation to use. See :ref:`adc-esp32_attenuation`.
- **update_interval** (*Optional*, :ref:`config-time`): The interval
to check the sensor. Defaults to ``15s``.
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
- All other options from :ref:`Sensor <config-sensor>` and :ref:`MQTT Component <config-mqtt-component>`.
.. note::
On the ESP8266, the voltage range is 0 to 1.0V - so to measure any higher voltage you need to scale the voltage
down using, for example, a voltage divider circuit.
.. _adc-esp32_attenuation:
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ESP32 Attenuation
~~~~~~~~~~~~~~~~~
On the ESP32, the voltage measured with the ADC caps out at 1.1V by default as the sensing range
or the attenuation of the ADC is set to ``0db`` by default.
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To measure voltages higher than 1.1V, set ``attenuation`` to one of the `following values
<http://esp-idf.readthedocs.io/en/latest/api-reference/peripherals/adc.html#_CPPv225adc1_config_channel_atten14adc1_channel_t11adc_atten_t>`__:
- ``0db`` for a full-scale voltage of 1.1V (default)
- ``2.5db`` for a full-scale voltage of 1.5V
- ``6db`` for a full-scale voltage of 2.2V
- ``11db`` for a full-scale voltage of 3.9V
See Also
^^^^^^^^
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- :ref:`sensor-filters`
- :doc:`ads1115`
- :doc:`max6675`
- :doc:`API Reference </api/sensor/adc-sensor>`