Please, proceed carefully following the tips published in this blog, specially when Main Power is involved. I'm not responsible for any damages caused by what is written in this blog.
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Saturday, 30 September 2017

Home Automation System - MQTT, SONOFF and OpenHAB v. 2

It's time to integrate MQTT and OpenHAB v.2.

As already said in a previous post (http://domoticsduino.blogspot.com/2017/08/home-automation-system-sonoff-and-mqtt_19.html), actually I have a SONOFF Basic already installed which drives a garden lamp. As we already know, it's already setup with MQTT and so let's start the OpenHAB integration.

I followed step by step the Tasmota wiki, in the integration section (https://github.com/arendst/Sonoff-Tasmota/wiki/openHAB) and so, as first step, I installed some ADDONS in OpenHAB:

Now I have to setup the MQTT connection to the MQTT broker which runs on the same Raspberry PI 3 as OpenHAB 2; so I have to edit the configuration file /etc/openhab2/config/mqtt.cfg directly through the linux shell (nano or vi) or using Eclipse SmartHome Designer, an advanced text editor optimized for OpenHAB v.2 configuration files. I used it. Its setup is very simple and then it needs to know the OpenHAB configuration files path. In my case I setup a network drive (called Z) for a samba share automatically defined by the installation of openHABianPI.

In particular, the configuration parameters I edited are the following ones:

serve and port of the MQTT broker

openHAB client Id for the MQTT connection

Username for the MQTT connection

Password for the MQTT connection

Defines if the broker should retain the messages sent to it

openhabianpi-mqtt is the logical name of the MQTT connection; in OpenHAB we could have many MQTT connections and in the items configuration we use this name as reference.

If you don't make mistakes, during the OpenHAB boot you may find log messages as following:

Ok, now I will configure items and the sitemap .

So, I created a file called sonoffbasic01.items in the folder /etc/openhab2/items in which I setup my new items.

I defined a "Switch" object ("light" category) which was linked to the full topic mqtt of the SONOFF Basic 01 tasmota/garden/light/%topic%/%prefix%/. Here is the syntax:

Switch Garden_Light_1Lamp "Garden 1-Lamp"      <light>
                     <[openhabianpi- mqtt:tasmota/garden/light/sonoffbasic01/tele/STATE:state:JSONPATH($.POWER)],

For info about syntax of .items files please see official documentation http://docs.openhab.org/configuration/items.html

In this way I created an item called Garden_Light_1Lamp linked to MQTT messages of topic defined in the {...} block

Then, I added this new item in my sitemap . So, I edited sitemap definition file, appending the following rows:

Frame label="Lights" {

Switch     item=Garden_Light_1Lamp        label="Garden Light 1 Lamp"       icon="switch"


After saved this file, OpenHAB updated the sitemap and the "lights" section appears

Here is a short video about my test: