Add "Delta" filter to the Filter integration, suppressing minor variation reports from high-rate sensors without delaying large variations

[amaurylam]

Integration name

Filter

Link to integration documentation on our website

https://www.home-assistant.io/integrations/filter/

Describe the enhancement

Some sensors (e.g. power or temperature related) may send frequent (every few seconds) reports of minor variations that are not really useful and significant, and waste resources (especially SQL database space) as well as making historical visualizations slower.

Currently, the Filter integration provides a throttle & time_throttle filters that can help reduce high frequency reports. I believe however these are not adapted to all use cases, especially when large variations should still be reported as soon as possible (like to trigger an automation).

A new delta filter would skip new reports in close vicinity of the last reported value. Unlike throttle & time_throttle, delta would:

1. suppress all non-significant reports (throttle & time_throttle are reducing, but not suppressing them)
2. avoid adding latency to the significant variations

Use cases

I have lot of power- and temperature-change related automations, and would like sudden variations to be reported instantly.

Unfortunately many of these sensors do not provide adjustable reporting thresholds, and are flooding the database with very small, non significant reports.

Anything else?

ESPHome has such a "Delta" filter https://esphome.io/components/sensor/#delta:

This filter stores the last value passed through this filter and only passes incoming values through if incoming value is sufficiently different from the previously passed one. This difference can be calculated in two ways an absolute difference or a percentage difference.

Not all devices being ESPHome-based, I believe having a similar feature in Home Assistant could be really helpful when an integration or device configuration does not provides a way to reduce frequent reports of non-significant variations.

[github-actions[bot]]

🏷️ I've automatically added the integration: filter label to help categorize this feature request.