Has anyone built out a self-hosted home alarm system? Something like ADT, but entirely self-hosted?

I’m wondering if this is possible with some combination of Frigate, Home Assistant, and something called Alarmo?

Or can a simple alarm system be created with just Frigate? I was thinking something simple like putting a camera inside my house when I leave. Then if any motion is detected inside of the house, activate a siren to scare potential burglars.