Home Automation System - SONOFF and MQTT together


I'm ready to test MQTT communication with my SONOFF Basic, also connected to a real button to light up my garden lamp.

I think it's important to be able to manage lights through standard buttons and switch, not only by Home Automation Software as openHAB and others, to avoid failures due to network problems.

So, I did another little hack to SONOFF: I soldered two little wire to its push button; these wires will be linked to a standard button on the wall.

Here are the wires connected to the button on the SONOFF

In this way, the standard button will activate the relays in the same way the button on the SONOFF or the APP will.

Last thing, to close the SONOFF with its case I have to make a little hole on the side to let the wires passing by:

Now, it's time to connect the SONOFF with the main power and link a standard button with the wires. In the INPUT pin I connected phase and neutral of the main power and in the OUTPUT pin I connected phase and neutral of the garden lamp.

Ok, after a little test all is working as expected. I pushed the button twice and lamp lighted up and down Thanks again to Piero who helped me to link the sonoff to the main power.

Now I can inspect the MQTT messages involved.

I use the web console, opening it through a internet browser, typing the ip address of the SONOFF in the address bar. Then, accessing the "Console" men├╣ I can take a look at the MQTT messages.

The first thing I noticed is the telemetry messages, sended by device about every 10 seconds (this timeout is managed by the TELEPERIOD parameter); the message content is a JSON string, which contains many informations (POWER, the state of the relay is the most interesting one for me in this moment); the MQTT topic is tasmota/garden/light/sonoffbasic01/tele/STATE, following what I wrote in a previous post (https://www.domoticsduino.cloud/en/blog/1/iot-smarthome/post/2017/08/home-automation-system-sonoff-and-mqtt.html).

In the following screenshot, the marked lines show the MQTT messages sequence:

After I pushed the button for the first time. the relay went on the ON state and the system sent a MQTT message with topic tasmota/garden/light/sonoffbasic01/stat/RESULT, with content POWER: ON. This is the confirmation sent by the device; the command has been well understood. When the relay changed its state to ON, the device sent another MQTT message with topic tasmota/garden/light/sonoffbasic01/stat/POWER and value ON. Now the relay is active and the lamp is ON.

The next telemetry messages confirmed this too. The POWER variable now has the value ON.

Then I pressed the button for the second time: the relay changes its state to OFF and the system sent the following MQTT messages:
tasmota/garden/light/sonoffbasic01/stat/RESULT{POWER: OFF} and tasmota/garden/light/sonoffbasic01/stat/POWEROFF. Now the lamp is OFF.

We get the same behaviour using the TOGGLE button on the web interface.

or sending POWER ON and POWER OFF commands directly from the web console.

As last step, I powered on the lamp using the MQTT POWER ON message, using a standard MQTT client, connected to our broker.

Normally I use MQTT-SPY, a very useful java software which permits to send and receive MQTT messages.

My message must belong to the topic tasmota/garden/light/sonoffbasic01/cmnd/POWER and must have the ON value. The lamp will turn ON.

Home Automation System - SONOFF and MQTT


Ok, it's time to get all the power of SONOFF.

Just to summarize, I've got a SONOFF Pow and a SONOFF Basic, both of them with TASMOTA firmware on board.

Using this fantastic firmware, I could control the device through serial comms, web api (http) and MQTT, a very good protocol for IoT purpose, thanks to its lightweight footprint. I spoke about MQTT in a previous post (see https://www.domoticsduino.cloud/en/blog/1/iot-smarthome/post/2017/07/home-automation-system-discovering.html)

I will use mostly the MQTT protocol; so, I have to setup SONOFFs to use it, entering the MQTT broker informations and the topics. As usual, the official Wiki pages help us (see https://github.com/arendst/Sonoff-Tasmota/wiki/MQTT-Features)

For those not able to run a local MQTT broker (Mosquitto is a good free broker), it is possible to use, only for testing purpose, some free public MQTT broker (example: Mosquitto Test Server, Hive MQ and Eclipse)

Browsing the configuration pages on the SONOFF web console, you could enter all the MQTT informations. You can open the SONOFF web console using your browser and typing the ip address in the address bar. A web page similar to the following one will be shown:

Clicking on "Configuration" ==>

We will use mainly the "Configure MQTT" option: the others are self-explained.

Here, I entered the Host (ip address or host name) and the Port (1883 is the MQTT default one) for the MQTT broker.

The Client ID field is a simple string which identifies the device on the MQTT broker. It will be better to be univocal among all the devices.

User and Password fields are used for broker authentication (highly recommended!!!)

Topic and Full Topic fields are the most important one for the MQTT protocol. Here you can find some information about them: https://github.com/arendst/Sonoff-Tasmota/wiki/MQTT-Features#mqtt-topic-definition

- Topic: normally used to identify the device; it will be part of the MQTT Full Topic. It will be better to be univocal among all the devices.

- Full Topic: is the complete topic used for MQTT messages.

Inside Full Topic, we could use two variables called %topic% and %prefix%.

%topic% will be replaced by one of the following system variables, according to the real situation: Topic, GroupTopic, ButtonTopic, SwitchTopic e MqttClient.

%prefix% identifies the type of message and could take three distinct values, corresponding to the folloing system variables: Prefix1, Prefix2 and Prefix3

- Prefix1 = cmnd, used for command messages
- Prefix2 = stat, used for status messages
- Prefix3 = tele, used for telemetry messages

When I speak about system variables, I mean a list of configurable TASMOTA properties for every device. There are so many...Here you can find the complete list: https://github.com/arendst/Sonoff-Tasmota/wiki/Commands#command-overview

Here is my SONOFF Basic configuration:

Topic = sonoffbasic01

Full Topic = tasmota/garden/light/%topic%/%prefix%/

For Topic and Full Topic I followed a naming convention, in order to understand the mean of a message, just reading its topic.

The Topic, as said before, identifies the single device; so I used the type of device followed by a progressive number. For example, the topic of the SONOFF Pow will be sonoffpow02. The same topic string will be used also as network name and mqtt client id for the device.

The naming convention for the Full Topic is: firmware/zone/type/%topic%/%prefix%/

I would like to clarify that these are not rules but only suggestions. I chose this naming convention, you could use another one. It's up to you...

The final step is to enable MQTT protocol on the device, looking for the MQTT enable flag in the Configure Other page.

Well, finally now I'm ready to test my SONOFF with MQTT.


A small update about a configuration error I found later


Home Automation System - OpenHAB 2 on Raspberry PI 3


It's time to setup my Home Automation System. I chose OpenHAB v.2, see my previous post https://www.domoticsduino.cloud/en/blog/1/iot-smarthome/post/2017/07/home-automation-system-discovering.html)

My target is to install OpenHAB v.2 and all related services on my brand new Raspberry PI 3; reading the official documentation (http://docs.openhab.org/installation/openhabian.html), I discovered OpenHABianPI, a custom operating system based on Raspian Lite, but optimized for OpenHAB. So I flashed on SD-CARD, with Etcher, a complete pre-configured image, downloaded from https://github.com/openhab/openhabian/releases. Then I plugged the SD-Card in the Raspberry slot and power it up, after connected a LAN cable (there is also a procedure to connect the raspberry direct to WiFi...http://docs.openhab.org/installation/openhabian.html#wifi-setup). The setup of OpenHABianPI automatically starts during boot and you can follow it through SSH. In about ten minutes the system will be ready.

The first thing to do is run the openhabian-config tool, which will let us to setup the complete system.

sudo openhabian-config

01 - Update and 02 - Upgrade System will keep the system updated and you will run them frequently.


- 10 - Apply Improvements ==> run all the submen├╣

- 20 - Optional Components ==> 21 - Log Viewer, 22 - Mosquitto (the MQTT broker) and 23 - Grafana (not mandatory but it's a very nice dashboard tool)

- 30 - System config ==> all optional except 34 - Change Passwords which will secure your system; 37 - Move root to USB;  is a very useful choice...it lets you to use an external USB Hard disk, instead of SD Card. I configured both my raspberries in this way, but I followed a manual procedure (see https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=44177&hilit=usb+stick+operating+system)

- 40 - openHAB related ==> 43 - Reverse Proxy very useful option to expose OpenHAB system on the internet and access it from everywhere; it will configure NGINX as SSL reverse proxy - pay attention that with this option your system will be exposed to internet and so if not well secured could permit to everyone to take control of your home devices.

Ok, OpenHAB is ready to use. I suggest you to take a look at the official documentation, tutorials and forum on the OpenHAB website http://docs.openhab.org/https://community.openhab.org

The official youtube channel is https://www.youtube.com/channel/UC7OK88DW0La_BJlcXZg8ydQ/feed

Just another useful info: OpenHAB could use a lot of services to persist data; one of these services uses InfluxDB, a NOSQL database. It lets OpenHAB to store historical data series which could be displayed as charts or tables. Grafana, the open source dashboard tool, is perfectly integrated with InfluxDB. You could also use the standard MYSQL RDBMS as a persistence service. I will use InfluxDB, and so I will install it on the same raspberry as openHAB (see https://docs.influxdata.com/influxdb/v1.3/introduction/installation/)

Let's summarize my system:

- OpenHAB v 2.1
- Mosquitto MQTT Broker, with authentication
- Grafana
- InfluxDB, as OpenHAB persistence service
- Reverse proxySSL with authentication, through NGINX , to expose OpenHAB and Grafana on the internet, in a secure way

If you are not able to setup and mantain reverse proxy, NAT and port forwarding, you could use My OpenHAB service, which lets you to exposed on the internet a local OpenHAB installation; registration is required.

Ok, we are ready to use our Home Automation System