calibrate_linear

Calibrate your sensor values by using values you measured with an accurate “truth” source.

Configuration variables:

• method (Optional, string): The method for calculating the linear function(s). One of least_squares or exact. Defaults to least_squares.
• datapoints (Required): The list of datapoints.

First, collect a bunch of values of what the sensor shows and what the real value should be. For temperature, this can for example be achieved by using an accurate thermometer. For other sensors like power sensor this can be done by connecting a known load and then writing down the value the sensor shows.

# Example configuration entry
- platform: dht
  # ...
  temperature:
    name: "DHT22 Temperature"
    filters:
      - calibrate_linear:
         method: least_squares
         datapoints:
          # Map 0.0 (from sensor) to 1.0 (true value)
          - 0.0 -> 1.0
          - 10.0 -> 12.1

The arguments are a list of data points, each in the form MEASURED -> TRUTH. Depending on the method ESPHome will then either fit a linear equation to the values (using least squares) or connect the values exactly using multiple linear equations. You need to supply at least two values. When using least_squares and more than two values are given a linear solution will be calculated and may not represent each value exactly.