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133 lines
4.0 KiB
ReStructuredText
LTR390 UV and Ambient Light Sensor
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==================================================
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.. seo::
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:description: Instructions for setting up LTR390 UV and light sensor
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:image: ltr390.jpg
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The ``ltr390`` sensor platform allows you to use your LTR390 UV and ambient
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light sensor
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(`datasheet <https://optoelectronics.liteon.com/upload/download/DS86-2015-0004/LTR-390UV_Final_%20DS_V1%201.pdf>`__, `Adafruit`_) with ESPHome.
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The :ref:`I²C Bus <i2c>` is required to be set up in your configuration for this sensor to work.
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.. figure:: images/ltr390-full.jpg
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:align: center
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:width: 80.0%
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.. _Adafruit: https://www.adafruit.com/product/4831
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.. code-block:: yaml
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sensor:
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- platform: ltr390
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uv_index:
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name: "UV Index"
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uv:
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name: "UV Sensor Counts"
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light:
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name: "Light"
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ambient_light:
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name: "Light Sensor Counts"
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Configuration variables:
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------------------------
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- **uv_index** (*Optional*): UV index (UVI). All options from :ref:`Sensor <config-sensor>`.
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- **uv** (*Optional*): Sensor counts for the UV sensor (#). All options from :ref:`Sensor <config-sensor>`.
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- **light** (*Optional*): Lux of ambient light (lx). All options from :ref:`Sensor <config-sensor>`.
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- **ambient_light** (*Optional*): Sensor counts for the Ambient light sensor (#). All options from :ref:`Sensor <config-sensor>`.
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- **gain** (*Optional*, string): Adjusts the sensitivity of the sensor. A larger value means higher sensitivity. Default is ``"X18"``, see table below for options.
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- **resolution** (*Optional*, int): ADC resolution. Higher resolutions require longer sensor integration times. Default is ``20``, see table below for options.
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- **window_correction_factor** (*Optional*, float): Window correction factor. Use larger values when using under tinted windows. Default is ``1.0``, must be ``>= 1.0``.
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- **address** (*Optional*, int): Manually specify the I²C address of the sensor. Default is ``0x53``.
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- **update_interval** (*Optional*, :ref:`config-time`): The interval to check the
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sensor. Defaults to ``60s``. It is recommended that the update interval is at least 1 second since updates can take up to 800ms when using a high resolution value.
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Lux and UVI Formulas
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--------------------
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.. math::
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\text{lux} = \frac{0.6 \times \text{als}}{\text{gain} \times \frac{\text{int}}{100} } \times \text{wfac}
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.. math::
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\text{UVI} = \frac{\text{uv}}{\text{sensitivity}} \times \text{wfac}
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where:
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- ``als`` and ``uv`` are the sensor values.
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- ``gain`` is the sensor gain, see the table below for details.
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- ``int`` is the integration time in ms and is tied to the resolution, see the table below for details.
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- ``sensitivity`` is the sensor's count per UVI. See note below for details.
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- ``wfac`` is the window correction factor.
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It is recommended to use the defaults of ``X18`` gain and resolution of 20 bits when UV Index sensing is required since
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the data sheet only provides accurate conversion formula for this combination. The UVI value is linearly scaled from
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this reference point when using other combinations of gain and resolution, which may be slightly inaccurate. The scaling
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formula is:
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.. math::
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\text{sensitivity} = 2300 \times \frac{\text{gain}}{18} \times \frac{\text{int}}{400}
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where :math:`2300` is the sensor count per UVI at the default configuration.
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Gain
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----
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.. list-table::
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:widths: 25 25
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:header-rows: 1
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* - Configuration value
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- gain
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* - X1
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- 1
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* - X3
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- 3
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* - X6
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- 6
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* - X9
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- 9
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* - X18
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- 18
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Resolution
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----------
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.. list-table::
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:widths: 25 25 10
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:header-rows: 1
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* - Configuration value
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- Resolution (bits)
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- Integration Time (ms)
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* - 16
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- 16
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- 25
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* - 17
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- 17
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- 50
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* - 18
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- 18
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- 100
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* - 19
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- 19
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- 200
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* - 20
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- 20
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- 400
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See Also
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--------
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- :doc:`/components/sensor/bh1750`
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- :doc:`/components/sensor/tsl2561`
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- `TEMT6000 <https://devices.esphome.io/devices/temt6000>`__
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- :ref:`sensor-filters`
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- :apiref:`ltr390/ltr390.h`
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- :ghedit:`Edit`
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