MCP3008 I/O Expander

The Microchip Technology Inc. MCP3008 devices are successive approximation 10-bit Analogto-Digital (A/D) converters with on-board sample and hold circuitry.

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MCP3008

The MCP3008 component allows you to use MCP3008 8-Channel 10-Bit A/D Converter (datasheet, Adafruit) in ESPHome. It uses the SPI Bus 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)

# 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:

MCP3008 Component

  • id (Required, 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, 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, Time): The interval to check the sensor. Defaults to 1s.