94 lines
3.1 KiB
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94 lines
3.1 KiB
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MCP3008 I/O Expander
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====================
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.. seo::
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:description: Instructions for setting up MCP3008 10 Bit Analog to Digital Converter in ESPHome.
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:keywords: MCP3008
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:image: images/mcp3008.jpg
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The Microchip Technology Inc. MCP3008
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devices are successive approximation 10-bit Analogto-Digital (A/D) converters with on-board sample and
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hold circuitry.
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.. figure:: images/mcp3008.jpg
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:align: center
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:width: 50.0%
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.. _mcp3008-component:
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Component/Hub
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-------------
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The MCP3008 component allows you to use MCP3008 8-Channel 10-Bit A/D Converter
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(`datasheet <http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf>`__,
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`Adafruit <https://www.adafruit.com/product/856>`__) in ESPHome.
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It uses the :ref:`SPI Bus <spi>` for communication.
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Once configured, you can use any of the 8 pins as
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sensors for your projects.
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Each pin will respond with a voltage calculated off of the reference_voltage (default is 3.3v).
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It calculates the voltage by multplying the reference_voltage * value on the pin (basically the percentage of VREF)
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Most configurations will set the reference_voltage = VREF (pin 13 on the chip)
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If you want just the scaled value you can use the read_data function
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``float MCP3008::read_data(uint8_t pin)``
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.. code-block:: yaml
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# Example configuration entry
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mcp3008:
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cs_pin: D8
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# Example config of sensors.
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# This is a NTCB3950 10K thermocoupler attached to pin 0
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# of the MCP3008 with a 10K resistor as a voltage divider.
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# See `resistance` and `ntc` platorms for other options
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sensor:
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- platform: mcp3008 # Attached to pin 0 of the MCP3008.
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reference_voltage: 3.19
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update_interval: 1s
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id: freezer_temp_source
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number: 0 # MCP3008 pin number
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- platform: resistance
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id: freezer_resistance_sensor
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sensor: freezer_temp_source
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configuration: DOWNSTREAM
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resistor: 10kOhm
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- platform: ntc
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id: freezer_temp
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sensor: freezer_resistance_sensor
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calibration:
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b_constant: 3950
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reference_temperature: 25°C
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reference_resistance: 10kOhm
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name: Freezer Temperature
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Configuration variables:
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- **id** (**Required**, :ref:`config-id`): The id to use for this MCP3008 component.
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- **cs_pin** (**Required**, int): The SPI cable select pin to use
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Sensor
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------
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The ``mcp3008`` sensor allows you to use your MCP3008 10-Bit A/D Converter sensors with ESPHome.
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First, setup a :ref:`MCP3008 Hub <mcp3008-component>` for your MCP3008 sensor and then use this
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sensor platform to create individual sensors that will report the voltage to Home Assistant.
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Configuration variables:
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- **id** (**Required**, :ref:`config-id`): The id of the parent MCP3008 component.
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- **number** (**Required**, int): The pin number of the MCP3008
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- **reference_voltage** (*Optional*, float): The reference voltage. Defaults to ``3.3V``.
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- **update_interval** (*Optional*, :ref:`config-time`): The interval to check the sensor. Defaults to ``1s``.
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See Also
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--------
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- :ref:`spi`
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- :apiref:`mcp3008/mcp3008.h`
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- :ghedit:`Edit`
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