Home Automation/Presence

I’ve been thinking about home automation a bit recently, and I realized that what I want as a big part of a system is some sort of generic presence-system. I’m imagining something along the lines of:

  • Small/cheap nodes that can be plugged in around a house/space
  • The nodes would form a mesh and talk to each other
  • Nodes would determine the strength of a signal (Bluetooth LE?) and “discuss” it amongst each other to determine which one you’re closest to, and thus roughly “where” you are (triangulate your location based on signal strengths)
  • Nodes would all connect to a server/service (could be locally-hosted), where they would broadcast your current location somehow. Maybe something like a Socket.IO server, so that other services could connect and receive live updates of location changes?

I wonder if this could be hacked together from iBeacons somehow, or if it’s too much the reverse of what they’re intended for? Does this already exist? Is there a better/simpler solution already available?