Added MCP3008 (#591)

* Added MCP3008

* PR Comment Changes

* Travis Fix

* format and simplified example

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

components/mcp3008.rst

@@ -0,0 +1,74 @@
+MCP3008 I/O Expander
+====================
+
+.. seo::
+    :description: Instructions for setting up MCP3008 10 Bit Analog to Digital Converter in ESPHome.
+    :image: mcp3008.png
+
+.. note::
+
+    This page is incomplete and could some work. If you want to contribute, please read the
+    :doc:`contributing guide </guides/contributing>`. This page is missing:
+
+      - An image for the front page.
+      - Formal documentation of the mcp3008 sensor entry (parent, update_interval, number, etc.)
+      - See Dallas sensor for reference model
+
+The Microchip Technology Inc. MCP3008
+devices are successive approximation 10-bit Analogto-Digital (A/D) converters with on-board sample and
+hold circuitry. Each pin will respond with a 0-1023 result depending on the voltage it is reading
+
+MCP3008
+-------
+
+The MCP3008 component allows you to use MCP3008 8-Channel 10-Bit A/D Converter
+(`datasheet <http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf>`__,
+`Adafruit <https://www.adafruit.com/product/856>`__) in ESPHome.
+It uses the :ref:`SPI Bus <spi>` for communication.
+
+Once configured, you can use any of the 8 pins as
+sensors for your projects.
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    mcp3008:
+      cs_pin: D8
+
+    # Example config of sensors.
+    # This is a NTCB3950 10K thermocoupler attached to pin 0
+    # of the MCP3008 with a 10K resistor as a voltage divider.
+    # See `resistance` and `ntc` platorms for other options
+    sensor:
+      - platform: mcp3008             # Attached to pin 0 of the MCP3008.
+                                      # The result will be a reading from 0-1023
+        update_interval: 1s
+        id: freezer_temp_source
+        number: 0                     # pin number
+      - platform: resistance
+        id: freezer_resistance_sensor
+        sensor: freezer_temp_source
+        configuration: DOWNSTREAM
+        resistor: 10kOhm
+      - platform: ntc
+        id: freezer_temp
+        sensor: freezer_resistance_sensor
+        calibration:
+          b_constant: 3950
+          reference_temperature: 25°C
+          reference_resistance: 10kOhm
+        name: Freezer Temperature
+
+Configuration variables:
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+- **id** (**Required**, :ref:`config-id`): The id to use for this MCP3008 component.
+- **cs_pin** (**Required**, int): The SPI cable select pin to use
+
+See Also
+--------
+
+- :ref:`spi`
+- :apiref:`mcp3008/mcp3008.h`
+- :ghedit:`Edit`
+

index.rst

@@ -330,6 +330,7 @@ Misc Components
 
     PCF8574 I/O Expander, components/pcf8574, pcf8574.jpg
     MCP230XX I/O Expander, components/mcp230xx, mcp230xx.svg
+    MCP3008 8-Channel 10-Bit A/D Converter, components/mcp3008, mcp3008.png
     SX1509 I/O Expander, components/sx1509, sx1509.jpg
     SIM800L, components/sim800l, sim800l.jpg
     DFPlayer, components/dfplayer, dfplayer.svg