Key based logins to your openHAB server console

Up until now, I was first doing a ssh login to my Pi3, then from there ssh to the well-known port and using the well-known password:

  • ssh openhab@localhost -p 8101

Apart from the security issues with the well-known password, this was adding another step of hassle whenever I needed to do some karaf operations or simply shut down my server for updates.

I always wanted to read up on Karaf to see how I can use key based logins, but somehow never got around to do that.

Thanks to a posting on the forums by Benj ( ), I can streamline this step:

  1. Create a key on the connecting client through your usual methods (e.g. ssh-keygen).
    • This step is optional if you already have a key you are using for your other systems.
  2. Copy the public key into openHAB’s (i.e. in userdata/etc/ or /var/lib/openhab2/etc/)
    • This follows the format [username]=[key],_g_:admingroup
    • Default username is openhab, but I prefer to use my “normal” username here too. Makes everything a tiny little bit easier
    • You can have multiple usernames if you decide to allow access to your openhab core for multiple users.
  3. Volia! Passwordless login

Of course, all of this might be moot when openHAB Cloud is released (on December 15th I believe).

Back from Hibernation

Even while playing a bit with my OpenHAB2 system a bit here and there, this particular side project was on an indeterminate hibernation…

Admittedly, I was thinking about building some stuff, maybe automating my windows blinds after all, or change my lighting system to something more automatable (MiLight was not really what I was expected at the beginning), but no big changes ever happened.

But no longer, I say! Back on active hacking, that’s what we are 🙂

Sensor reading scripts for openhab on github

For various reasons (not the least of them being that I am a geek prone to overengineering 🙂 ), my openhab installation consists of multiple Rasperry Pi nodes. The data collected is pushed via HTTP (upcoming: mqtt) to the server node.

Also, there are some precautions in place to avoid overloading the OH2 server while keeping a short response time to events. The first script published there is for the magnetic window contacts.

Without further ado, please find my scripts over at

My Java library for OpenCage Data has been discovered

Over the last six weeks or so, I was writing a frontend to the nice geocoding service at with the sources being stored at github.

As it always is the case, I never got around to really polishing the library and do a proper release. Imagine my surprise when I saw a post on the opencage data blog and a tweet mentioning me and my library.

Seems like I really have to do a proper release now, but only after my summer vacation… No coding allowed while visiting the relatives 🙂


I want a smart house

SmartHomeSoooooo…. I got bitten by the automate-your-living-environment bug, too.

Actually, my reasons for home automation started off a little bit differently. My house is heated with a Vaillant EcoCompact unit. Most of the time, this thing works pretty reliably. Unfortunately, some of the times, it just decides to get into a fault state and stops heating. More unfortunately, this is usually sometime in the morning and I discover the problem when I get only cold water in the shover. Without precise information how often and when this issue occurs, the maintenance company just comes to my place, tells me that they cannot find any fault and leave me with yet another bill.

The low-tech and works-for-everyone way of logging this information is simply putting a sheet of paper next to the heating unit and write down the dates, but what self-respecting geek would go with low-tech solutions?

Instead, I plan on setting up something that:

  • is fully automated
  • keeps logs for the maintenance company
  • notifies me before I get into the shower

An appropriate high-tech solution which appeals to my geeky sensibilities would be to add home automation functionality to my already overloaded server in the basement. Therefore……..

Enter “openHAB” 🙂