I would like to take advantage of an existing home automation system. I am also a developer, and probably want to contribute to the home automation system that I end up using, and adapt it to my needs. I have heard of the following home automation systems: fhem, iobroker, domoticz, openHAB. My take on these:

• fhem is written in Perl. I like learning programming languages, but never could bring myself to have more than a quick glance at Perl. I have avoided Perl so far, and have no interest in changing this for the purpose of home automation. fhem, therefore, is not for me.

• I like that it can be extended in C and Lua. I do not like their abstractions of “hardware” and “device”, particularly because all my temperature sensors would have to be attached to the fictive “virtual hardware” and I would have to fake their values using MQTT or REST. This feels like I have to work around how the system is supposed to function from day 1. Also, updating a value through REST results in confirmation, although the data is not actually stored. MQTT messages have to adhere to very strict, very verbose format. I do not like that MQTT sensors have to know the index number with which they have been added to Domoticz. A sensor ID or description should be enough.

• I like the nodejs approach. I do not like that iobroker is commercial software, and any contributions that I would make help the author to sell a product, while he does not pay me. I do not like that the system contacts the author’s website to check that my license is valid. I do not like the initial mandatory sending of my data to the author. I do not like the confusing documentation (just try to find out which version of nodejs is required). Documentation consists of many many instructions for entering specific commands, instead of simply listing dependencies. Many of these instructions are outdated - why are they still there? iobroker is for German speaking users only: English documentation is horrible, to the point of being impossible to understand. Tried the fritzbox adapter, it complains that it cannot cpnnect to my fritzbox even though the settings are correct.

• I like that it is written in Java, but I fear that it reqires too many system resources, and OSGi for development (Horror!). These impressions may be wrong, as I have not yet tried openHAB yet. the is my next step.

I’m also again considering to do everything on my own. So far, the none of the systems have looked very good. I also fear that the systems could get in my way when I want to do my temperature analysis. But first I will try openHAB.