Previously I installed some sensors around my home, and got them to update their status into an MQTT Message Broker. The Message Broker acts as a central nervous system for the apartment, making the status of sensors available to everything.
Knowing status alone is not enough, we must be able to "do" things with the knowledge. We want to be able to transform the status from one form of information to another, to make decisions by combining inputs from different things, and finally, to act ...