[sensors] High-pass and low-pass filters #5584
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Pull Request Overview
This PR adds documentation for two new sensor filters: high_pass and low_pass. These filters provide signal processing capabilities to remove high-frequency noise or low-frequency drift from sensor readings.
- Added documentation for high_pass and low_pass filters with explanations, formulas, and usage examples
- Integrated the new filters into the main sensor documentation index in alphabetical order
- Added filter examples to the comprehensive filter list
Reviewed Changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 7 comments.
| File | Description |
|---|---|
| content/components/sensor/filter/low_pass.md | New documentation for the low_pass filter with configuration details and example |
| content/components/sensor/filter/high_pass.md | New documentation for the high_pass filter with configuration details and example |
| content/components/sensor/_index.md | Added high_pass and low_pass filter sections and examples to the main sensor documentation |
| assuming the sensor values are sampled at a constant rate. This filter will remove low-frequency | ||
| components and offset from the sensor values. | ||
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| The formula for the high pass filter is: ``y[i] := α × y[i−1] + α × (x[i] − x[i−1])``, |
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Inconsistent multiplication symbol used. The formula uses × (Unicode multiplication sign) while the low_pass filter uses * (asterisk) in its formula. For consistency and to match code syntax conventions, use * instead of ×. Change α × y[i−1] + α × (x[i] − x[i−1]) to α * y[i−1] + α * (x[i] − x[i−1]).
| The formula for the high pass filter is: ``y[i] := α × y[i−1] + α × (x[i] − x[i−1])``, | |
| The formula for the high pass filter is: ``y[i] := α * y[i−1] + α * (x[i] − x[i−1])``, |
| headless: true | ||
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| Basic [low pass filter](https://en.wikipedia.org/wiki/Low-pass_filter>) for the sensor values, |
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The Wikipedia link has a malformed closing bracket. The link should end with ) instead of >). Change [low pass filter](https://en.wikipedia.org/wiki/Low-pass_filter>) to [low pass filter](https://en.wikipedia.org/wiki/Low-pass_filter).
| Basic [low pass filter](https://en.wikipedia.org/wiki/Low-pass_filter>) for the sensor values, | |
| Basic [low pass filter](https://en.wikipedia.org/wiki/Low-pass_filter) for the sensor values, |
| headless: true | ||
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| Basic [high pass filter](https://en.wikipedia.org/wiki/High-pass_filter>) for the sensor values, |
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The Wikipedia link has a malformed closing bracket. The link should end with ) instead of >). Change [high pass filter](https://en.wikipedia.org/wiki/High-pass_filter>) to [high pass filter](https://en.wikipedia.org/wiki/High-pass_filter).
| Basic [high pass filter](https://en.wikipedia.org/wiki/High-pass_filter>) for the sensor values, | |
| Basic [high pass filter](https://en.wikipedia.org/wiki/High-pass_filter) for the sensor values, |
| where ``x`` is the input value and ``y`` is the output value. | ||
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| A lower α implies that the output will respond more slowly to changes in the input but will also | ||
| be less influenced by noise. We can say the system has more inertia. A value of 0.5 (when time constant equal sampling period) might be a good starting point for experimentation. |
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Grammar error: "equal" should be "equals". Change "when time constant equal sampling period" to "when time constant equals sampling period".
| be less influenced by noise. We can say the system has more inertia. A value of 0.5 (when time constant equal sampling period) might be a good starting point for experimentation. | |
| be less influenced by noise. We can say the system has more inertia. A value of 0.5 (when time constant equals sampling period) might be a good starting point for experimentation. |
| even small changes in input. | ||
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| A small α implies that the output will decay quickly and will require large changes in the input | ||
| to cause the output to change much. A value of 0.5 (when time constant equal sampling period) might be a good starting point for experimentation. |
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Grammar error: "equal" should be "equals". Change "when time constant equal sampling period" to "when time constant equals sampling period".
| to cause the output to change much. A value of 0.5 (when time constant equal sampling period) might be a good starting point for experimentation. | |
| to cause the output to change much. A value of 0.5 (when time constant equals sampling period) might be a good starting point for experimentation. |
| # Example configuration entry | ||
| - platform: wifi_signal | ||
| # ... | ||
| filters: | ||
| - low_pass: 0.25 | ||
| ``` | ||
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The configuration variable description is incomplete and inconsistent with the example usage. The example shows - low_pass: 0.25 (using the filter name directly with a value), but the configuration variable is named alpha. Either clarify that the shorthand syntax sets the alpha parameter, or show the full configuration format. Compare with exponential_moving_average which shows both shorthand and full formats in its example.
| # Example configuration entry | |
| - platform: wifi_signal | |
| # ... | |
| filters: | |
| - low_pass: 0.25 | |
| ``` | |
| # Example configuration entry (shorthand) | |
| - platform: wifi_signal | |
| # ... | |
| filters: | |
| - low_pass: 0.25 # Shorthand: sets alpha to 0.25 | |
| # Example configuration entry (full format) | |
| - platform: wifi_signal | |
| # ... | |
| filters: | |
| - low_pass: | |
| alpha: 0.25 |
Note: The shorthand syntax (- low_pass: 0.25) is equivalent to the full format (- low_pass: { alpha: 0.25 }) and sets the alpha parameter.
| # Example configuration entry | ||
| - platform: wifi_signal | ||
| # ... | ||
| filters: | ||
| - high_pass: 0.75 | ||
| ``` | ||
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| Configuration variables: | ||
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| - **alpha** (*Required*, float): *Alpha* smoothing factor for the high pass filter. From 0 to 1. |
There was a problem hiding this comment.
The configuration variable description is incomplete and inconsistent with the example usage. The example shows - high_pass: 0.75 (using the filter name directly with a value), but the configuration variable is named alpha. Either clarify that the shorthand syntax sets the alpha parameter, or show the full configuration format. Compare with exponential_moving_average which shows both shorthand and full formats in its example.
| # Example configuration entry | |
| - platform: wifi_signal | |
| # ... | |
| filters: | |
| - high_pass: 0.75 | |
| ``` | |
| Configuration variables: | |
| - **alpha** (*Required*, float): *Alpha* smoothing factor for the high pass filter. From 0 to 1. | |
| # Example configuration entry (shorthand and full format) | |
| - platform: wifi_signal | |
| # ... | |
| filters: | |
| # Shorthand: sets alpha directly | |
| - high_pass: 0.75 | |
| # Full configuration format | |
| - high_pass: | |
| alpha: 0.75 |
Configuration variables:
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alpha (Required, float): Alpha smoothing factor for the high pass filter. From 0 to 1.
You can use the shorthand syntax
- high_pass: 0.75which is equivalent to- high_pass: { alpha: 0.75 }.
latonita
changed the title
1 participant
Description:
Related issue (if applicable): fixes
Pull request in esphome with YAML changes (if applicable):
Checklist:
I am merging into
nextbecause this is new documentation that has a matching pull-request in esphome as linked above.or
I am merging into
currentbecause this is a fix, change and/or adjustment in the current documentation and is not for a new component or feature.Link added in
/components/index.rstwhen creating new documents for new components or cookbook.