Add docs for sdp3x component (#1333)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

components/sensor/sdp3x.rst

@@ -0,0 +1,46 @@
+SDP3x Differential Pressure Sensor
+==================================
+
+.. seo::
+    :description: Instructions for setting up the SDP3x Differential Pressure sensor.
+    :image: images/sdp31.jpg
+    :keywords: SDP3x, SDP31, SDP32
+
+The SDP3x Differential Pressure sensor allows you to use your SDP3x
+(`datasheet <https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/8_Differential_Pressure/Datasheets/Sensirion_Differential_Pressure_Datasheet_SDP3x_Digital.pdf>`__,
+`sparkfun <https://www.sparkfun.com/products/17874>`__)
+sensors with ESPHome.
+
+.. figure:: images/sdp31.jpg
+    :align: center
+    :width: 30.0%
+
+    SDP31 Differential Pressure Sensor.
+    (Credit: `Sparkfun <https://www.sparkfun.com/products/17874>`__, image cropped and compressed)
+
+.. _Sparkfun: https://www.sparkfun.com/products/17874
+
+To use the sensor, set up an :ref:`I²C Bus <i2c>` and connect the sensor to the specified pins. 
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    - platform: sdp3x
+      name: "HVAC Filter Pressure drop"
+      id: filter_pressure
+
+Configuration variables:
+------------------------
+
+- **name** (**Required**, string): The name for this sensor.
+- **id** (*Optional*, :ref:`config-id`): Set the ID of this sensor for lambdas/multiple sensors.
+- **address** (*Optional*, int): The I²C address of the sensor. Defaults to ``0x21``.
+- **update_interval** (*Optional*, :ref:`config-time`): The interval to check the sensor. Defaults to ``60s``.
+- All other options from :ref:`Sensor <config-sensor>`.
+
+See Also
+--------
+
+- :ref:`sensor-filters`
+- :apiref:`sdp3x/sdp3x.h`
+- :ghedit:`Edit`

index.rst

@@ -323,6 +323,7 @@ Environmental
     NTC Thermistor, components/sensor/ntc, ntc.jpg, Temperature
     RuuviTag, components/sensor/ruuvitag, ruuvitag.jpg, Temperature & Humidity & Accelerometer
     SCD30, components/sensor/scd30, scd30.jpg, Temperature & Humidity
+    SDP3x, components/sensor/sdp3x, sdp31.jpg, Pressure
     SHTCx, components/sensor/shtcx, shtc3.jpg, Temperature & Humidity
     SHT3X-D, components/sensor/sht3xd, sht3xd.jpg, Temperature & Humidity
     SHT4X, components/sensor/sht4x, sht4x.jpg, Temperature & Humidity