Controlling your lights from your phone is neat, but true smart homes run themselves. Home Assistant features a visual automation engine that lets you connect devices that normally wouldn't talk to each other.
Overview
Because Home Assistant runs locally on your LocalNode, automations execute instantly. When you walk past a motion sensor, the lights turn on in milliseconds, compared to the 2-3 second delay common with cloud-based platforms like Alexa or SmartThings.
The three parts of an Automation
Every automation in Home Assistant consists of three core building blocks:
Triggers (When): The event that starts the automation. (e.g., "When the motion sensor detects movement", or "At exactly 10:00 PM").
Conditions (And if): Rules that must be true for the automation to proceed. (e.g., "Only if nobody is home", or "Only if the sun has set").
Actions (Then do): What actually happens. (e.g., "Turn on the living room lights", or "Send a notification to my phone").
Example: Porch lights at sunset
Let's build a classic automation: turning the front porch lights on when it gets dark, and turning them off at 11:00 PM.
Open Home Assistant and go to Settings > Automations & Scenes.
Click + Create Automation in the bottom right, then select Create new automation.
Add a Trigger: Click "Add trigger" > "Sun" > "Sunset". You can even add an offset, like "-00:15:00" to trigger 15 minutes before sunset.
Add an Action: Click "Add action" > "Device". Select your Porch Light switch, and under Action, select "Turn on".
Click Save, and name it "Turn on porch lights".
Now, create a second automation for turning them off:
Click + Create Automation again.
Add a Trigger: Click "Add trigger" > "Time". Enter "23:00:00" (11:00 PM).
Add an Action: Click "Add action" > "Device". Select the Porch Light, and select "Turn off".
💡 Tip: You can click the three dots in the top right of the automation editor and select "Show trace". This brings up a flowchart showing exactly how and when the automation last fired, which is invaluable for debugging why a light didn't turn on.
Using Blueprints for complex logic
Some automations are notoriously difficult to write from scratch, like "Turn on the bathroom light with motion, keep it on as long as there is motion, but turn it off 2 minutes after motion stops."
Home Assistant uses Blueprints to solve this. A Blueprint is a pre-written automation template shared by the community.
Go to Settings > Automations & Scenes > Blueprints tab.
Home Assistant comes with a "Motion-activated Light" blueprint by default. Click Create Automation next to it.
Simply select your motion sensor from the first dropdown, and your light bulb from the second dropdown.
Type "120" in the wait time box.
Save it. You just configured a highly complex automation in three clicks.
