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Get alerted when a door is left open: automations HomeKit can't do

Updated 2 July 2026

Ask HomeKit to notify you "when the garage door has been open for 15 minutes" and you hit a wall: HomeKit triggers fire on state changes, not on duration. There is no timer condition, so the classic left-the-fridge-open and forgot-the-garage-door alerts are impossible to build in Apple's Home app – and always have been.

The workaround is a virtual sensor: a synthetic accessory that turns on only after a real accessory has held a state for a set time. Apple Home can then automate and notify on the virtual sensor like on any real one.

How it works with Itsyhome

Itsyhome for macOS can publish its own HomeKit bridge carrying read-only virtual sensors (contact, motion, occupancy, leak, smoke, CO, CO₂). You pair the bridge into Apple Home by scanning a QR code, and the sensors become first-class HomeKit accessories – visible in Apple Home, usable in any automation, and included in HomeKit notifications.

The sensors are driven by built-in automations of the form "WHEN a HomeKit accessory holds a state FOR a duration THEN set a virtual sensor", with optional re-pulsing to repeat the alert. The Mac watches the real accessory, does the timing HomeKit cannot, and flips the virtual sensor.

Setup

  1. 1

    Create the virtual sensor

    In Itsyhome on the Mac, open Settings → HomeKit bridge, enable the bridge, and add a virtual sensor – for example a contact sensor named "Garage door left open".

  2. 2

    Pair the bridge into Apple Home

    Scan the QR code shown in Itsyhome (or type the setup code) from the Home app on your iPhone, like adding any accessory. Pairings and the bridge identity persist across restarts.

  3. 3

    Add the duration automation

    Create the built-in automation: WHEN the real garage door contact sensor is "open" FOR 15 minutes THEN set "Garage door left open" to triggered. Optionally enable re-pulsing so it re-fires every N minutes while the door stays open.

  4. 4

    Automate in Apple Home

    In the Home app, enable notifications for the virtual sensor or build an automation on it – flash a light, announce on HomePods, anything HomeKit can do when a sensor triggers. To your whole household it behaves like real hardware.

Other conditions this unlocks

  • Fridge or freezer door ajar for more than 2 minutes.
  • A window left open for 30 minutes while the heating is on (combine with a multi-condition automation).
  • No motion in a room for an hour → treat as vacancy and switch things off.
  • Repeated nagging: re-pulse the sensor every 10 minutes until the door is closed.
  • Webhook-driven states: any external system can set a virtual sensor over HTTP, bringing non-HomeKit signals into Apple Home.

Frequently asked questions

Can HomeKit notify me when a door has been open for 15 minutes?

Not natively – HomeKit automations trigger on state changes and have no duration condition. The workaround is a virtual sensor: Itsyhome on macOS watches the real sensor, waits out the duration, then triggers a virtual HomeKit sensor that Apple Home can notify and automate on.

What is a virtual HomeKit sensor?

A synthetic accessory published over the HomeKit Accessory Protocol by software instead of hardware. Itsyhome's bridge publishes read-only virtual contact, motion, occupancy, leak, smoke, CO, and CO₂ sensors that appear in Apple Home like real devices, driven by duration automations or webhooks.

Does this need my Mac to be running?

Yes – the Mac runs the bridge and does the timing, so it needs to be awake for the automations to fire (a desktop Mac or a Mac that never sleeps is ideal). The virtual sensors live in HomeKit, so notifications reach every family member's iPhone as normal.

Can other apps or scripts set the virtual sensors?

Yes. Sensor state can be set by name through Itsyhome's webhook server, so any script, Home Assistant automation, or external system can flip a virtual sensor over HTTP and drive Apple Home notifications from it.

Related guides

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