Updated Mcp3008 to support reference_voltage and voltage_sampler::VoltageSampler (#874)

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

changelog/v1.15.0.rst

@@ -41,7 +41,7 @@ Changelog - Version 1.15.0 - September 13, 2020
     PID Controller, components/climate/pid, function.svg
     IR Remote Climate, components/climate/ir_climate, air-conditioner-ir.svg
     HTTP Request, components/http_request, connection.svg
-    MCP3008 8-Channel 10-Bit A/D Converter, components/mcp3008, mcp3008.png
+    MCP3008 8-Channel 10-Bit A/D Converter, components/mcp3008, mcp3008.jpg
     SN74HC595 I/O Expander, components/sn74hc595, sn74hc595.jpg
     TM1651 Battery Display, components/tm1651, tm1651_battery_display.jpg
     RF Bridge, components/rf_bridge, rf_bridge.jpg

components/sensor/mcp3008.rst

@@ -3,20 +3,17 @@ 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
+    :keywords: MCP3008
+    :image: images/mcp3008.jpg
 
 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
+hold circuitry. 
+
+.. figure:: images/mcp3008.jpg
+    :align: center
+    :width: 50.0%
+
 
 MCP3008
 -------
@@ -29,6 +26,14 @@ It uses the :ref:`SPI Bus <spi>` for communication.
 Once configured, you can use any of the 8 pins as
 sensors for your projects.
 
+Each pin will respond with a voltage calculated off of the reference_voltage (default is 3.3v).
+It calculates the voltage by multplying the reference_voltage * value on the pin (basically the percentage of VREF)
+
+Most configurations will set the reference_voltage = VREF (pin 13 on the chip)
+
+If you want just the scaled value you can use the read_data function
+  ``float MCP3008::read_data(uint8_t pin)``
+
 .. code-block:: yaml
 
     # Example configuration entry
@@ -41,10 +46,10 @@ sensors for your projects.
     # 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
+        reference_voltage: 3.19
         update_interval: 1s
         id: freezer_temp_source
-        number: 0                     # pin number
+        number: 0                     # MCP3008 pin number
       - platform: resistance
         id: freezer_resistance_sensor
         sensor: freezer_temp_source
@@ -61,14 +66,21 @@ sensors for your projects.
 
 Configuration variables:
 ~~~~~~~~~~~~~~~~~~~~~~~~
-
+MCP3008 Component
+*****************
 - **id** (**Required**, :ref:`config-id`): The id to use for this MCP3008 component.
 - **cs_pin** (**Required**, int): The SPI cable select pin to use
 
+MCP3008 Sensor Component
+************************
+- **id** (**Required**, :ref:`config-id`): The id of the parent MCP3008 component.
+- **number** (**Required**, int): The pin number of the MCP3008
+- **reference_voltage** (*Optional*, float): The reference voltage. Defaults to ``3.3V``.
+- **update_interval** (*Optional*, :ref:`config-time`): The interval to check the sensor. Defaults to ``1s``.
+
 See Also
 --------
 
 - :ref:`spi`
 - :apiref:`mcp3008/mcp3008.h`
 - :ghedit:`Edit`
-

index.rst

@@ -133,6 +133,7 @@ Sensor Components
     MAX31856, components/sensor/max31856, max31856.jpg
     MAX31865, components/sensor/max31865, max31865.jpg
     MAX6675, components/sensor/max6675, max6675.jpg
+    MCP3008, components/sensor/mcp3008, mcp3008.jpg
     MCP9808, components/sensor/mcp9808, mcp9808.jpg
     MH-Z19, components/sensor/mhz19, mhz19.jpg
     MPU6050, components/sensor/mpu6050, mpu6050.jpg
@@ -356,7 +357,6 @@ Misc Components
     PCF8574 I/O Expander, components/pcf8574, pcf8574.jpg
     MCP230XX I/O Expander - I²C Bus, components/mcp230xx, mcp230xx.svg
     MCP23SXX I/O Expander - SPI Bus, components/mcp23Sxx, mcp230xx.svg
-    MCP3008 8-Channel 10-Bit A/D Converter, components/mcp3008, mcp3008.png
     SX1509 I/O Expander, components/sx1509, sx1509.jpg
     SN74HC595 I/O Expander, components/sn74hc595, sn74hc595.jpg
     SIM800L, components/sim800l, sim800l.jpg