I've been running HA for a while, and it's been working well; I haven't had to change much in a few months. That being said, it's fun to tinker with it, and I'm curious to hear what kind of automations the rest of the community is using. What automations are you most proud of? What are your favorite? What kind of interesting automations have you written?
My personal favorite is an automation that displays the current "apparent" temperature on a Hue bulb. It takes an average of the temperature, humidity, and luminance around my property and uses the average to compute an "apparent" (feels like) temperature. Then it applies a cosine function to the apparent temperature (to approximate how people feel temperature change), uses the resulting value to calculate a level between blue and red in CIELAB (a perceptually uniform color space), converts the results to RGB, and sets the color value of the hue bulb. The result is a bulb that changes color so that the change in color (as perceived by the eye) mirrors how the temperature "feels" outside. Ultimately what that means is that we can look at a small lamp with the hue bulb and say "It feels cold outside; we should put on a coat." It's probably overkill, but it was a fun programming exercise. We've started saying things like "It's really blue today, I don't feel like going out."
I'd really enjoy reading what kind of interesting automations everyone else has written.
15 minutes before my alarm or my partner's goes off, the bedroom lights start to gradually fade on for the next half hour. A few minutes after that the HVAC gets reset to daytime temperatures. The hallway light turns on before we get out there, and if it is still dark outside (this time of year in Canada!) the entrance lights and kitchen lights also turn on ahead of time. Lastly it gets the dehumidifier started for the day and turns off Night Mode across all my automations.
Usually it results in us waking up gently, a bit before our alarms and we can turn them off without any blaring sounds.