I've always thought it would be cool to deck out my house not with Google Home or Alexa, but with my own systems built with Raspberry Pis and software/hardware

I've always thought it would be cool to deck out my house not with Google Home or Alexa, but with my own systems built with Raspberry Pis and software/hardware I built myself. Is there anyone out there trying to build an open-source alternative to all these commercial systems?