MQTT and openHAB adventure

Some people asked me to share my MQTT setup in regard to openHAB and I agreed to do so. In this blog post I will explain and describe in more detail my current setup primarily on the heating subject.

But first some background info. A long time ago I installed openHAB 1.6 on a Raspberry Pi 2 and started with some Homematic and Enocean (devkit) devices, but learned there were more interesting alternatives and fell in love with the MySensors project. This project allows you to create your own home automation devices with Arduino and alike hardware and provides a library that will handle all communication between the devices and openHAB. Since I started with MySensors I have used MQTT to connect to openHAB, so I already had a working MQTT setup when the OpenTherm gateway entered the house.

Setting up MQTT is pretty straightforward. Below I describe the steps I took to install and configure MQTT in combination with openHAB.

  1. $ sudo apt-get install mosquitto
    This installs version 0.15 of the software from the default repository. In my recent journey to upgrade MySensors from 1.5 to 2.1 I had to upgrade the mosquitto software to a newer release to make it work again.
  2. Upgrade mosquitto (optional)
    $ cd /etc/apt/sources.list.d/
    $ sudo wget
    $ sudo apt-get update
    $ sudo apt-get install mosquitto
  3. Start the moquitto service
    $ sudo service mosquitto start
  4. Install MQTT openHAB binding (assuming openHAB is installed from the repo).
    $ sudo apt-get install openhab-addon-binding-mqtt
    otherwise place the MQTT addon binding in the right directory
  5. Configure the openHAB MQTT binding
    edit the openHAB main config file: /etc/openhab/configurations/openhab.cfg
  6. Restart openHAB
    $ sudo service openhab restart
  7. Check if the addon is loaded and reports an connection:
    $ sudo tailf /var/log/openhab/openhab.log | grep -i mqtt
    2016-11-06 16:40:29.047 [INFO ] [.io.transport.mqtt.MqttService] – MQTT Service initialization completed.
    2016-11-06 16:40:29.050 [INFO ] [o.i.t.m.i.MqttBrokerConnection] – Starting MQTT broker connection ‘mybroker’

Now that openHAB is configured to listen to the MQTT message bus it’s time to hook up the OpenTherm gateway.

I will continue in another post to explain the OpenTherm gateway configuration and openHAB items and rules. Also some useful debugging commands which I use alot. This was drafted pretty quickly, so the layout is not that nice. Hopefully I will find some time to tidy up the styling..

That’s it for now, more to follow on this subject soon!

Fixing runaway setpoint value

It’s not really a fix. It’s better to speak of a workaround to correct the setpoint of the household thermostat which slowly shifts over time (see the graph above). I lack knowledge to fix the source, which is most probably the OTGW software. So I have created a rule in openHAB to check and fix the setpoint every time it gets updated.

If someone else experience this behavior, the rule below works for me!

rule "Correct setpoint"
  Item ot_setpoint received update
  var float CurrentSetpoint = (ot_setpoint.state as DecimalType).floatValue
  logInfo("home.rules", "ot_setpoint before: " + CurrentSetpoint)

  var float CorrectSetpoint = Math::round(CurrentSetpoint.floatValue*2)/2.0f
  logInfo("home.rules", "ot_setpoint after: " + CorrectSetpoint)

  if (CorrectSetpoint != CurrentSetpoint) {
    postUpdate(ot_setpoint, CorrectSetpoint)
    logInfo("home.rules", "ot_setpoint correction performed")

Install SafeNet eToken PRO on Ubuntu 16.04 LTS

Since I run Ubuntu on my workstation at work I need a working eToken, so every time I upgrade (follow LTS releases) I have to make sure the eToken works. Because some have reported the installation steps I have described for 14.04 are not working for 16.04 I have decided to update the steps for the latest LTS.

Download the new client software at:

Unpack the source:


Prepare the install:

mkdir temp ; sudo mount -o loop SAC_9_1_Linux.iso ./temp


dpkg -i temp/Installation/Standard/DEB/SafenetAuthenticationClient-9.1.7-0_amd64.deb