As you walk around your house with a Bluetooth beacon like Google's Eddystone, Estimote, an iBeacon, or having your phone advertising acting as a beacon, Happy Bubbles presence detectors will listen for those signals and send them over WiFi to an MQTT server you define. A subscriber program on the server will determine which presence detector you're closest to and make that information available over an API. It can also notify your other connected devices when it detects you moved from one location to another. So it can turn off lights and music when you leave your house, or turn them on when you walk into the living room. The system is designed to be very flexible so you can make it do whatever you want.
Each Happy Bubbles presence detector listens for Bluetooth low energy advertisements around it that are sent constantly by things like iBeacons, or even your phone if you make it act as a beacon. The presence detector also connects to your home WiFi and an MQTT server of your choice. Each detector will then send the beacon advertisements it sees, as well as their signal strengths, to the MQTT server over WiFi.
We've provided a sample presence server that subscribes to the MQTT topics sent by the presence detectors and analyzes the signal strengths to see which detector a beacon is closest to. It emits its findings over MQTT and also sends out changes, to tell you when you've left one detector and come within range of another. So you can script actions based on when you enter or leave a location. But you can also just look up where a beacon is closest to, to help you with stuff like finding an object you might stick a beacon onto.
You can then subscribe to the topics to see yourself and do other things with it. That's why this whole thing is open source and entirely under your control, because chances are you'll be much more creative with this stuff than we are, so we want to enable that as best we can.