mirror of
https://github.com/esphome/esphome-docs.git
synced 2024-11-08 09:52:07 +01:00
87 lines
2.7 KiB
ReStructuredText
87 lines
2.7 KiB
ReStructuredText
Analog To Digital Sensor
|
|
========================
|
|
|
|
.. seo::
|
|
:description: Instructions for setting up built-in analog voltage sensors.
|
|
:image: flash.png
|
|
|
|
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.
|
|
|
|
.. figure:: images/adc-ui.png
|
|
:align: center
|
|
:width: 80.0%
|
|
|
|
.. code-block:: yaml
|
|
|
|
# Example configuration entry
|
|
sensor:
|
|
- platform: adc
|
|
pin: A0
|
|
name: "Living Room Brightness"
|
|
update_interval: 60s
|
|
|
|
Configuration variables:
|
|
------------------------
|
|
|
|
- **pin** (**Required**, :ref:`config-pin`): The pin to measure the voltage on.
|
|
Or on the ESP8266 alternatively also ``VCC``, see :ref:`adc-esp8266_vcc`.
|
|
- **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 ``60s``.
|
|
- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
|
|
- All other options from :ref:`Sensor <config-sensor>`.
|
|
|
|
.. 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:
|
|
|
|
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.
|
|
|
|
To measure voltages higher than 1.1V, set ``attenuation`` to one of the `following values
|
|
<https://docs.espressif.com/projects/esp-idf/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
|
|
|
|
.. _adc-esp8266_vcc:
|
|
|
|
ESP8266 Measuring VCC
|
|
---------------------
|
|
|
|
On the ESP8266 you can even measure the voltage the chip is getting. This can be useful in situations
|
|
where you want to shut down the chip if the voltage is low when using a battery.
|
|
|
|
To measure the VCC voltage, set ``pin:`` to ``VCC`` and make sure nothing is connected to the ``A0`` pin.
|
|
|
|
.. code-block:: yaml
|
|
|
|
sensor:
|
|
- platform: adc
|
|
pin: VCC
|
|
name: "VCC Voltage"
|
|
|
|
See Also
|
|
--------
|
|
|
|
- :ref:`sensor-filters`
|
|
- :doc:`ads1115`
|
|
- :doc:`max6675`
|
|
- :apiref:`sensor/adc.h`
|
|
- :ghedit:`Edit`
|
|
|
|
.. disqus::
|