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Lite-On Ambient Light & Proximity Sensors
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=========================================
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.. seo::
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:description: Instructions for setting up LTR301, LTR501, LTR558 ambient light sensors/proximity sensors with ESPHome.
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:image: ltr501.jpg
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:keywords: LTR-301, LTR-501, LTR-558
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.. figure:: images/ltr501-full.jpg
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:align: center
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:width: 60.0%
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LTR-501 on a breadboard from Olimex
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.. figure:: images/ltr501-ui.png
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:align: center
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:width: 60.0%
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LTR-501 Sensor in Home Assistant UI.
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The ``ltr501`` sensor platform allows you to use a range of LiteOn ambient light and proximity sensors
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with ESPHome.
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The supported family of sensors includes:
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- Ambient Light Sensor **LTR-301ALS**
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- Integrated Ambient Light and Proximity Sensors **LTR-501ALS** and **LTR-558ALS**
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The LTR-501 device is available on a 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
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configuration for this sensor to work. I²C address is ``0x23``.
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Proximity sensors are the same sort of sensors that you find in phones and tablets to disable the screen when you hold
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the device up to your ear. They might be useful for automated turning on or off of displays and control panels.
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.. _Olimex: https://www.olimex.com/Products/Modules/Sensors/MOD-LTR-501ALS/open-source-hardware
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Ambient light sensing
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---------------------
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These sensors have a linear response over a wide dynamic range from 0.01 lux to 64k lux and are well suited
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to applications under high ambient brightness. There are two gain settings (1X, 150X) available for use.
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Use higher gain for dimmer areas.
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These devices consist of two photodiodes: a *CH0* diode that is sensitive to both visible and infrared light and
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a *CH1* diode that is sensitive only to infrared light.
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**Note**: These sensors do not have internal data checking and do not indicate any errors if
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data is not reliable. The sensors can be easily saturated if the gain is too high or the integration time is too long. In this
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case, readings can be very strange. It's recommended to use automatic mode with a starting gain of 1X (default) and a starting
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integration time of 100ms (default) or even 50ms (if the sensor is in a very bright environment). Automatic mode with starting
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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
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Excerpt from the datasheet:
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.. code-block::
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RATIO = CH1/(CH0+CH1)
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IF (RATIO < 0.45)
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ALS_LUX = (1.7743 * CH0 + 1.1059 * CH1) / ALS_GAIN / ALS_INT
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ELSEIF (RATIO < 0.64 && RATIO >= 0.45)
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ALS_LUX = (3.7725 * CH0 – 1.3363 * CH1) / ALS_GAIN / ALS_INT
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ELSEIF (RATIO < 0.85 && RATIO >= 0.64)
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ALS_LUX = (1.6903 * CH0 - 0.1693 * CH1) / ALS_GAIN / ALS_INT
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ELSE
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ALS_LUX = 0
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END
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where:
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- ``CH0`` and ``CH1`` are the sensor values (measurement counts) for Visible + IR (Ch0) and IR only (Ch1) sensors respectively.
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- ``ALS_GAIN`` is the gain multiplier
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- ``ALS_INT`` is the integration time in ms/100
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ALS Gain levels
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^^^^^^^^^^^^^^^
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The table lists gain values and corresponding illuminance range:
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========= ================================
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Gain Illuminance range
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========= ================================
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``1X`` 2 lux to 64k lux (default)
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``150X`` 0.01 lux to 320 lux
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========= ================================
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This Wikipedia `article <https://en.wikipedia.org/wiki/Lux>`__ has a table of some lux values for comparison.
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The following table lists possible gain and integration time combinations:
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================== ======== =============== ======== ========
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Gain / Int.time 50 ms 100 ms 200 ms 400 ms
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================== ======== =============== ======== ========
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``1X`` ✓ ✓ (default)
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``150X`` ✓ ✓ ✓
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================== ======== =============== ======== ========
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Proximity sensing
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-----------------
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The proximity sensor has a built-in emitter and detector. The sensor detects reflected IR light from the emitter and
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gives a raw count value inversely proportional to the distance squared. A decrease in the count value means an object is getting
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further away from the sensor (and vice-versa). Neither of the datasheets provide any information on how to convert
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the raw count value to distance. The only way to do so is to test the sensor yourself and select the threshold
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according to your needs and environment. Exact values will depend on the type of the object, its color and
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reflectivity.
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Example configuration
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---------------------
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.. code-block:: yaml
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sensor:
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- platform: ltr501
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type: ALS_PS # .. or ALS or PS
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ambient_light: "Ambient light"
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# PS only section
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ps_cooldown: 5 s
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ps_high_threshold: 500
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on_ps_high_threshold:
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then:
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- .... # do something - light up the screen for example
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ps_counts:
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name: "Proximity counts"
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Configuration variables
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-----------------------
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- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
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- **address** (*Optional*, int): Manually specify the I²C address of the sensor. Default is ``0x23``.
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- **type** (*Optional*, string): The type of the sensor. Valid values are ``ALS_PS`` *(default)* for
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integrated sensors, ``ALS`` for ambient light only or ``PS`` for proximity only devices.
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- **auto_mode** (*Optional*, boolean): Automatic gain and integration time selection. Defaults to True.
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- **gain** (*Optional*, string): The gain the device will use. Higher values are better in low-light conditions.
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Valid values are ``1X`` *(default)*, ``150X``.
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- **integration_time** (*Optional*, :ref:`config-time`):
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The amount of time sensors are exposed. Longer means more accurate values.
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Valid values are: ``50ms``, ``100ms`` *(default)*, ``200ms``, ``400ms``.
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- **glass_attenuation_factor** (*Optional*, float): The attenuation factor of glass if it's behind some glass
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or plastic facia. Default is ``1.0`` means ``100%`` transmissivity. ``2`` means ``50%`` transmissivity etc.
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- **update_interval** (*Optional*, :ref:`config-time`): The interval for checking the sensors.
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Defaults to ``60s``.
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- **ps_cooldown** (*Optional*, :ref:`config-time`): The "cooldown" period after the proximity sensor is triggered.
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Helps to avoid multiple calls. Defaults to ``5s``.
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- **ps_gain** (*Optional*, string): The gain the device will use for proximity sensor. Higher values are better in low-light conditions.
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Valid values are ``1X`` *(default)*, ``4X``, ``8X``, ``16X``.
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- **ps_high_threshold** (*Optional*, int): The threshold for the proximity sensor to trigger on object getting closer.
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Defaults to ``65535``, which implies it will never be triggered.
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- **ps_low_threshold** (*Optional*, int): The threshold for the proximity sensor to trigger on object getting further away.
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Defaults to ``0``, which implies it will never be triggered.
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- **on_ps_high_threshold** (*Optional*): Actions to perform when the proximity sensor is triggered
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on object getting closer.
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- **on_ps_low_threshold** (*Optional*): Actions to perform when the proximity sensor is triggered
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on object getting further away.
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Sensors
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^^^^^^^
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This component offers five sensors for ALS-equipped devices and one sensor for PS-equipped devices.
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You can configure all or any subset of these sensors. Each configured sensor is reported separately
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on each ``update_interval``. Each is an ESPHome :ref:`sensor <config-sensor>` and may be configured
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accordingly; if you don’t need to configure additional :ref:`sensor <config-sensor>` variables, you
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may simply use the shorthand syntax for the sensor. For example: ``ambient_light: "Ambient light"``
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- **ambient_light** (*Optional*): Illuminance of ambient light, close to human eye spectre, lx.
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- **infrared_counts** (*Optional*): Sensor counts from the IR-sensitive sensor (*CH1*), counts.
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- **full_spectrum_counts** (*Optional*): Sensor counts from the sensor sensitive to both visible light and IR (*CH0*), counts.
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- **actual_gain** (*Optional*): Gain value used to measure data, multiplier. Particularly useful when "auto_mode" is selected.
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- **actual_integration_time** (*Optional*): Integration time used to measure data, ms. Particularly useful when "auto_mode" is selected.
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- **ps_counts** (*Optional*) - Raw 11-bit reading from proximity sensor, counts.
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See Also
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--------
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- `LTR-501ALS datasheet <https://github.com/latonita/datasheets-storage/blob/main/sensors/LTR-501ALS-01.pdf>`__
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- `LTR-558ALS datasheet <https://github.com/latonita/datasheets-storage/blob/main/sensors/ltr-558als-01%20LITE-S-A0000286415-1.pdf>`__
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- `LTR-301ALS datasheet <https://github.com/latonita/datasheets-storage/blob/main/sensors/LTR-301ALS-01_PrelimDS_ver1.pdf>`__
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- :apiref:`ltr501/ltr501.h`
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- :ghedit:`Edit`
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