This article is part of my 1000² Smart Home project. Check out the Architecture and Software and then move on to Hardware. An most importantly, check the Lessons learned and why I did what I did. There are already some first results, connecting all parts of the system.
There is plenty of software to use in home automation, but of course I decided to stay with open source and free options.
In recent years there have been multiple new “controller” type of software, which is the type that is suppose to control, manage, display, graph, talk etc while working with products from multiple manufacturers. This gives the user a nice central interface to control and display, coupled, of course with automation rules and scheduling.
OpenHAB is my favourite of the few I have played with. I have selected it because it is open and has a comprehensive list of devices it can talk to, although I own extremely few such devices. They, of course, have rules for the user to program behaviour, nice graphs and working on persistence. On the negative side, they have multiple user interfaces, with occasional features scattered, making none of them the ultimate winner. I am planning on using Open HAB for the user interface and some rule making.
Node Red is a cool new idea, coming from IBM, implementing flow based design. Multiple people use it for home automation and just like Open HAB it has a plethora of ready made possibilities to interface with existing products. It can run quite smoothly on a raspberry Pi offering a web interface for designing the flow. It provides ways to build a dashboard through simple hierarchies and predefined widgets, although some things are more limited than I would like.
At this moment is seems like the best support to try crazy stuff, like making the umbrella blink if it is going to rain tomorrow.
MQTT is something that is not really needed, using either Node Red or Open HAB messages can have any kind of format. But I decided to use it because it provides structure and can interface different software components, as plenty have built in support. The principle of MQTT is simple: there’s a central broker through which all messages go through. A message is made of a topic, which is hierarchical, (like house/first_floor/bathroom/temperature) and a payload containing the value. I find the hierarchical naming a little bit against human nature but it does provide the benefit of easily selecting similar things through wildcards.