Device Changed
Category: Trigger
Fires when a HomeKit device's state changes — a light turns on, a sensor reading updates, a lock is toggled. You can trigger on a single device or an entire service group.
When to use
- Respond to a motion sensor detecting movement
- React when a door lock is opened or closed
- Trigger actions when temperature crosses a threshold
- Monitor a group of lights (e.g. "All Living Room Lights") for any change
Configuration
- Source mode — Choose between a single Device or a Service Group
- Device / Group — Select the accessory or group to watch
- Characteristic — Which property to monitor (e.g.
power_state,brightness,temperature) - To value (optional) — Only trigger when the value changes to this specific value
- From value (optional) — Only trigger when the value changes from this specific value
- Numeric thresholds (optional) — For numeric values like temperature or brightness, trigger when the value crosses above or below a threshold
Output data
Downstream nodes can reference the trigger data:
{{ trigger.to_value }}— The new value after the change{{ trigger.from_value }}— The previous value before the change{{ trigger.accessory_id }}— ID of the specific device that changed{{ trigger.characteristic_type }}— Which characteristic changed
For service group triggers, trigger.accessory_id is the specific device within the group that triggered.
Examples
Turn off all lights when motion sensor clears:
- Device Changed → motion sensor,
motion_detected, to =0 - Delay → 5 minutes
- Set Device → all lights off
Alert when temperature exceeds threshold:
- Device Changed → temperature sensor, above 30
- Notify → "Temperature is {{ trigger.to_value }}!"
Tips
- Service group triggers fire for each device in the group independently — if 3 lights turn on, the automation runs 3 times
- Use
fromandtofilters together to catch specific transitions (e.g. from 0 to 1 = "just turned on") - Numeric thresholds fire on crossing — if the value is already above the threshold and stays above, it won't fire again