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Support for light sensors LTR-501, LTR-301, LTR-558 #3616

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196 changes: 196 additions & 0 deletions components/sensor/ltr501.rst
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Lite-On Ambient Light & Proximity Sensors
=========================================

.. seo::
:description: Instructions for setting up LTR301, LTR501, LTR558 ambient light sensors/proximity sensors with ESPHome.
:image: ltr501.jpg
:keywords: LTR-301, LTR-501, LTR-558


.. figure:: images/ltr501-full.jpg
:align: center
:width: 60.0%

LTR-501 on a breadboard from Olimex

.. figure:: images/ltr501-ui.png
:align: center
:width: 60.0%

LTR-501 Sensor in Home Assistant UI.

The ``ltr501`` sensor platform allows you to use family of several LiteOn ambient light and proximity sensors
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with ESPHome.

The supported family of sensors includes:

- Ambient Light Sensor **LTR-301ALS**
- Integrated Ambient Light and Proximity Sensors **LTR-501ALS** and **LTR-558ALS**

The LTR-501 device is available on breakout board from `Olimex`_.
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The sensors are very similar and share the same datasheet. The :ref:`I²C Bus <i2c>` is required to be set up in your
configuration for this sensor to work. I²C address is ``0x23``.

Proximity sensors are the same sort of sensors that you find in phones and tablets to disable the screen when you hold
the device up to your ear. They might be useful for automated turning on or off of displays and control panels.

.. _Olimex: https://www.olimex.com/Products/Modules/Sensors/MOD-LTR-501ALS/open-source-hardware

Ambient light sensing
---------------------

Sensor platform provides a linear response over a wide dynamic range from 0.01 lux to 64k lux and is well suited
to applications under high ambient brightness. There are two gain settings (1X, 150X) available for user to configure.
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Use higher gain for dimmer areas.

Devices consists of two photodiodes: *CH0* diode that is sensitive to both visible and infrared light and
*CH1* diode that is sensitive only to infrared light.
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**Note**: Important to note, that these sensors do not have internal data checking and do not provide any errors if
data is not reliable. Sensor can be easily saturated if gain is too high or integration time is too long. In this
case readings can be very strange. It's recommended to use automatic mode with starting gain of 1X (default) and starting
integration time of 100ms (default) or even 50ms (if sensor is in very bright environment). Automatic mode with starting
gain of 150X is not recommended, use it only if you are sure brightness will never exceed 200-300 lx.
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Ambient light illuminance calculation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Excerpt from the datasheet:

.. code-block::

RATIO = CH1/(CH0+CH1)
IF (RATIO < 0.45)
ALS_LUX = (1.7743 * CH0 + 1.1059 * CH1) / ALS_GAIN / ALS_INT
ELSEIF (RATIO < 0.64 && RATIO >= 0.45)
ALS_LUX = (3.7725 * CH0 – 1.3363 * CH1) / ALS_GAIN / ALS_INT
ELSEIF (RATIO < 0.85 && RATIO >= 0.64)
ALS_LUX = (1.6903 * CH0 - 0.1693 * CH1) / ALS_GAIN / ALS_INT
ELSE
ALS_LUX = 0
END


where:

- ``CH0`` and ``CH1`` are the sensor values (measurement counts) for Visible + IR (Ch0) and IR only (Ch1) sensors respectively.
- ``ALS_GAIN`` is the gain multiplier
- ``ALS_INT`` is the integration time in ms/100


ALS Gain levels
^^^^^^^^^^^^^^^

The table lists gain values and corresponding illuminance range:

========= ================================
Gain Illuminance range
========= ================================
``1X`` 2 lux to 64k lux (default)
``150X`` 0.01 lux to 320 lux
========= ================================


This Wikipedia `article <https://en.wikipedia.org/wiki/Lux>`__ has a table of some lux values for comparison.


The following table lists possible gain and integration time combinations:

================== ======== =============== ======== ========
Gain / Int.time 50 ms 100 ms 200 ms 400 ms
================== ======== =============== ======== ========
``1X`` ✓ ✓ (default)
``150X`` ✓ ✓ ✓
================== ======== =============== ======== ========


Proximity sensing
-----------------

Proximity sensor has built-in emitter and detector. The sensor detects reflected IR light from the emitter and
gives a raw count value inversely exponential to the distance. Drop in the count value means an object is getting
further away from the sensor, and vice versa. Neither of the datasheets provides any information on how to convert
the raw count value to distance. The only way to do it is to test the sensor yourself and select the threshold
according to your needs and environment. Exact numbers will depend on the type of the object, its color and
reflectivity.
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Example configuration
---------------------

.. code-block:: yaml

i2c:
# ...

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sensor:
- platform: ltr501
address: 0x23
update_interval: 60s
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type: ALS_PS # .. or ALS or PS
ambient_light: "Ambient light"
# PS only section
ps_cooldown: 5 s
ps_high_threshold: 500
on_ps_high_threshold:
then:
- .... # do something - light up the screen for example
ps_counts:
name: "Proximity counts"


Configuration variables
-----------------------
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- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
- **address** (*Optional*, int): Manually specify the I²C address of the sensor. Default is ``0x23``.
- **type** (*Optional*, string): The type of the sensor. Valid values are ``ALS_PS`` *(default)* for
integrated sensors, ``ALS`` for ambient light only or ``PS`` for proximity only devices.
- **auto_mode** (*Optional*, boolean): Automatic gain and integration time selection. Defaults to True.
- **gain** (*Optional*, string): The gain the device will use. Higher values are better in low-light conditions.
Valid values are ``1X`` *(default)*, ``150X``.
- **integration_time** (*Optional*, :ref:`config-time`):
The amount of time sensors are exposed. Longer means more accurate values.
Valid values are: ``50ms``, ``100ms`` *(default)*, ``200ms``, ``400ms``.
- **glass_attenuation_factor** (*Optional*, float): The attenuation factor of glass if it's behind some glass
or plastic facia. Default is ``1.0`` means ``100%`` transmissivity. ``2`` means ``50%`` transmissivity etc.
- **update_interval** (*Optional*, :ref:`config-time`): The interval for checking the sensors.
Defaults to ``60s``.
- **ps_cooldown** (*Optional*, :ref:`config-time`): The "cooldown" period after the proximity sensor is triggered.
Helps to avoid multiple calls. Defaults to ``5s``.
- **ps_gain** (*Optional*, string): The gain the device will use for proximity sensor. Higher values are better in low-light conditions.
Valid values are ``1X`` *(default)*, ``4X``, ``8X``, ``16X``.
- **ps_high_threshold** (*Optional*, int): The threshold for the proximity sensor to trigger on object getting closer.
Defaults to ``65535``, which implies it will never be triggered.
- **ps_low_threshold** (*Optional*, int): The threshold for the proximity sensor to trigger on object getting further away.
Defaults to ``0``, which implies it will never be triggered.
- **on_ps_high_threshold** (*Optional*): Actions to perform when the proximity sensor is triggered
on object getting closer.
- **on_ps_low_threshold** (*Optional*): Actions to perform when the proximity sensor is triggered
on object getting further away.

Sensors
^^^^^^^
This component offers five sensors for ALS-enabled devices and one sensor for PS-enabled devices.
You can configure all or any subset of the sensors. Each configured sensor is reported separately
on each ``update_interval``. **name** option is required for the sensor. All other options from
:ref:`Sensor <config-sensor>`. If you don't need to configure any other sensor options, you can
use the simplified syntax for the sensor: ``ambient_light: "Ambient light"``, for example.
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- **ambient_light** (*Optional*): Illuminance of ambient light, close to human eye spectre, lx.
- **infrared_counts** (*Optional*): Sensor counts from the IR-sensitive sensor (*CH1*), counts.
- **full_spectrum_counts** (*Optional*): Sensor counts from the sensor sensitive to both visible light and IR (*CH0*), counts.
- **actual_gain** (*Optional*): Gain value used to measure data, multiplier. Particularly useful when "auto_mode" is selected.
- **actual_integration_time** (*Optional*): Integration time used to measure data, ms. Particularly useful when "auto_mode" is selected.
- **ps_counts** (*Optional*) - Raw 11-bit reading from proximity sensor, counts.


See Also
--------

- `LTR-501ALS datasheet <https://github.com/latonita/datasheets-storage/blob/main/sensors/LTR-501ALS-01.pdf>`__
- `LTR-558ALS datasheet <https://github.com/latonita/datasheets-storage/blob/main/sensors/ltr-558als-01%20LITE-S-A0000286415-1.pdf>`__
- `LTR-301ALS datasheet <https://github.com/latonita/datasheets-storage/blob/main/sensors/LTR-301ALS-01_PrelimDS_ver1.pdf>`__
- :apiref:`ltr501/ltr501.h`
- :ghedit:`Edit`
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3 changes: 3 additions & 0 deletions index.rst
Original file line number Diff line number Diff line change
Expand Up @@ -438,6 +438,9 @@ Light
APDS9960, components/sensor/apds9960, apds9960.jpg, Colour & Gesture
AS7341, components/sensor/as7341, as7341.jpg, Spectral Color Sensor
BH1750, components/sensor/bh1750, bh1750.jpg, Lux
LTR301, components/sensor/ltr501, ltr501.jpg, Lux
LTR501, components/sensor/ltr501, ltr501.jpg, Lux & Proximity
LTR558, components/sensor/ltr501, ltr501.jpg, Lux & Proximity
LTR390, components/sensor/ltr390, ltr390.jpg, Lux & UV
MAX44009, components/sensor/max44009, max44009.svg, Lux
TCS34725, components/sensor/tcs34725, tcs34725.jpg, Lux & RGB colour
Expand Down