Alarmo is a free, open-source alarm integration for Home Assistant. It turns the door, window and motion sensors you already run locally into a proper alarm with away, home and night modes, entry and exit delays and user codes, without a vendor account or a monitoring contract.
Nobody watches the alarm for you: it can sound a siren and send notifications, but calling for help stays your job. It is only as dependable as the Home Assistant box it runs on, so give that box a battery backup.
