Add documentation for Shelly Dimmer 2 (#1753)

Co-authored-by: Richard Nauber <richard@nauber.dev>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

components/light/shelly_dimmer.rst

@@ -0,0 +1,99 @@
+Shelly Dimmer
+=============
+
+.. seo::
+    :description: Instructions for setting up a Shelly Dimmer 2.
+    :image: shellydimmer2.jpg
+    
+The ``shelly_dimmer`` component adds support for the dimming and power-metering functionality that can be found the `Shelly Dimmer 2 <https://shelly.cloud/knowledge-base/devices/shelly-dimmer-2/>`_. The interaction with mains is done via an STM32 microcontroller that is flashed with an `open source firmware <https://github.com/jamesturton/shelly-dimmer-stm32>`_.
+A detailed analysis of the Shelly Dimmer 2 hardware is given `here <https://github.com/arendst/Tasmota/issues/6914>`_.
+
+.. figure:: ../../images/shellydimmer2.jpg
+    :align: center
+    :width: 40.0%
+
+
+An example of a configuration of this component:
+
+.. code-block:: yaml
+
+    logger:
+        baud_rate: 0
+
+    uart:
+        tx_pin: 1
+        rx_pin: 3
+        baud_rate: 115200
+    sensor:
+
+    light:
+        - platform: shelly_dimmer
+          name: Shelly Dimmer 2 Light
+          id: thislight
+          power:
+            name: Shelly Dimmer 2 Light Power
+          voltage:
+            name: Shelly Dimmer 2 Light Voltage
+          current:
+            name: Shelly Dimmer 2 Light Current
+          max_brightness: 500
+          firmware:
+            version: "51.6"
+            update: true
+
+
+Configuration variables:
+------------------------
+
+- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
+- **uart_id** (*Optional*, :ref:`config-id`): Manually specify the ID of the UART hub. 
+
+.. note::
+
+    Currently, only the first hardware UART of the ESP is supported, which has to be configured like this:  
+
+    .. code-block:: yaml
+
+        uart:
+            tx_pin: 1
+            rx_pin: 3
+            baud_rate: 115200
+
+
+- **name** (**Required**, string): The name of the light.
+- **leading_edge** (**Optional**, boolean): `Dimming mode <https://en.wikipedia.org/wiki/Dimmer#Solid-state_dimmer>`_: "true" means leading edge, "false" (default) is trailing edge.
+- **min_brightness** (**Optional**, int): Minimum brightness value on a scale from 0..1000, the default is 0.
+- **max_brightness** (**Optional**, int): Maximum brightness value on a scale from 0..1000, the default is 1000.
+- **warmup_brightness** (**Optional**, int): Brightness threshold below which the dimmer switches on later in mains current cycle. `This might help with dimming LEDs <https://github.com/jamesturton/shelly-dimmer-stm32/pull/23>`_. The value is from 0..1000 with an default of 0.
+- **nrst_pin** (**Optional**, :ref:`config-pin`): Pin connected with "NRST" of STM32. The  default is "GPIO5".
+- **boot0_pin** (**Optional**, :ref:`config-pin`): Pin connected with "BOOT0" of STM32. The  default is "GPIO4".
+- **current** (**Optional**): Sensor of the current in Amperes. All options from
+  :ref:`Sensor <config-sensor>`.
+- **voltage** (**Optional**): Sensor of the voltage in Volts. Only accurate if neutral is connected. All options from :ref:`Sensor <config-sensor>`.
+- **power** (**Optional**): Sensor of the active power in Watts. Only accurate if neutral is connected. All options from :ref:`Sensor <config-sensor>`.
+- **firmware**  (**Optional**):
+    - **version**  (**Optional**): Version string of the `firmware <https://github.com/jamesturton/shelly-dimmer-stm32>`_ that will be expected on the microcontroller. The default is "51.6", another known-good firmware is "51.5".
+    - **url** (**Optional**): An URL to download the firmware from. Defaults to github for known firmware versions.
+    - **sha256** (**Optional**):  A hash to compare the downloaded firmware against. Defaults a proper hash of known firmware versions.
+    - **update** (**Optional**):  Should the firmware of the STM be updated if necessary? The default is false.
+
+.. note::
+
+    When flashing Shelly Dimmer with esphome for the first time, flashing the STM firmware is necessary too for the dimmer to work:
+
+    .. code-block:: yaml
+
+        firmware:
+          version: "51.6" #<-- set version here
+          update: true
+
+
+- All other options from :ref:`Light <config-light>`.
+
+
+See Also
+--------
+
+- :doc:`/components/light/index`
+- :apiref:`shelly_dimmer/light/shelly_dimmer.h`
+- :ghedit:`Edit`

index.rst

@@ -465,6 +465,7 @@ Light Components
     Light Partition, components/light/partition, color_lens.svg
 
     Tuya Dimmer, components/light/tuya, tuya.png
+    Shelly Dimmer, components/light/shelly_dimmer, shellydimmer2.jpg    
     Custom Light, components/light/custom, language-cpp.svg
 
     H-bridge Light, components/light/hbridge, brightness-medium.svg