Automation with JavaScript

You can read and write ioBroker objects manually, but you can also automate the process. ioBroker has three strategies for automation: Scenes (please do not confuse these with KNX scenes), Flows in Node-RED [5], and JavaScript. I'll focus on the most powerful of the three alternatives: writing your own small JavaScript programs.

The Scripts tab takes you to the built-in JavaScript development environment in ioBroker. Pressing the New Script icon creates an empty text file named Script1 in the common directory. You can rename this file as desired. Before saving the empty file, check the Help output box. In the built-in editor, you can start automating. To familiarize yourself with the JavaScript's ioBroker-specific extension, take a look at the documentation on GitHub [6].

The implementation of the previous automation example (TV button on remote control triggers the KNX Television scene, which in turn switches an additional Hue light) is shown in Listing 1. Line 1 contains the most important component: The on() statement defines a callback function that is used whenever the state of the harmony.0.Harmony-Hub.activities.currentActivity object changes. The object's complete path specification results from the hierarchical arrangement in the object tree. The specified string can be obtained in the Object view using the clipboard symbol above an object name.

The function then determines the value of the currentActivity object and displays it on the console together with its previous value for demonstration purposes. The switch() statement in Line 12 considers different values of the activity, and Line 16 finally triggers the KNX Television scene by writing to the corresponding ioBroker object using the setState() function. The value 0 represents the KNX scene with the number 1 (the value is the scene number minus one). For the adapter to actually set the value, you first need to set a third parameter to false. This sounds a bit illogical at first, but you'll find a detailed explanation on the ioBroker Wiki [7].

In the group monitor of the ETS software, you can see how the TV scene was triggered on the KNX side. The scene object with the KNX group address 15/4/8 receives the value 0, which means that the program retrieves scene 1.

The second on() statement in Line 21 also switches on the Hue pendant_lamp_front when someone activates the KNX Television scene. Of course, you could have packed the setState() function call from Line 28 directly under the first setState() call from the Harmony callback function. However, a separate callback function (as in Listing 1) has the advantage that the Hue lamp is switched on even if the KNX scene was not triggered via ioBroker.

Conclusions

With even a little knowledge of JavaScript, almost any smart home subsystem can be integrated into a larger whole via the ioBroker platform. This integration is possible because the ioBroker system provides a large number of available adapters and an ingenious object database. ioBroker is a top-ranking solution for cost-effective smart home networking within your own four walls.