esphome-docs/components/sensor/mcp3008.rst
2021-07-22 23:38:38 +02:00

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MCP3008 I/O Expander
====================
.. seo::
:description: Instructions for setting up MCP3008 10 Bit Analog to Digital Converter in ESPHome.
:keywords: MCP3008
:image: images/mcp3008.jpg
The Microchip Technology Inc. MCP3008
devices are successive approximation 10-bit Analog-to-Digital (A/D) converters with on-board sample and
hold circuitry.
.. figure:: images/mcp3008.jpg
:align: center
:width: 50.0%
.. _mcp3008-component:
Component/Hub
-------------
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.
Each pin will respond with a voltage calculated off of the reference_voltage (default is 3.3v).
It calculates the voltage by multiplying 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
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.
reference_voltage: 3.19
update_interval: 1s
id: freezer_temp_source
number: 0 # MCP3008 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
Sensor
------
The ``mcp3008`` sensor allows you to use your MCP3008 10-Bit A/D Converter sensors with ESPHome.
First, setup a :ref:`MCP3008 Hub <mcp3008-component>` for your MCP3008 sensor and then use this
sensor platform to create individual sensors that will report the voltage to Home Assistant.
Configuration variables:
- **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`