HowTo: ESPEasy - Configure MQTT Server and Subscribe to Topics

First open the configuration web page of your ESP8266 programmed with ESPEasy by entering its IP address into your web browser. Information on how to find out the IP address can also be found in the article Display/find out the IP address of the devices in the network summarized.

As soon as you have opened the configuration website, you must switch to the "Controllers" tab. To do this, click on the "Controllers" button.

Now click on the "Add" button in one of the empty rows.

This will redirect you to a page where a drop-down menu will be displayed.

Open the drop-down menu by clicking on it and select the entry "Home Assistant (openHAB) MQTT".

You will be redirected to the configuration page of this controller (=MQTT server). First you can choose if you want to enter the address of the MQTT server as hostname or IP address.

In the example shown here I use a hostname. But you can also use an IP address. If you do, you should configure your router so that the IP address is fixed.

You can apply the other settings as shown.

It is important that the port is set to the configured port of your MQTT server (1883 by default).

You must also enter the login details for your MQTT server if it requires authentication. To do this, enter the user name and password in the corresponding fields and check the "Use Extended Credentials" box.

You can configure the remaining settings as shown. For the sake of completeness, here is a short description.

• "Controller Client ID": Here you can specify the name/ID of your controller to the MQTT server.
• "Unique Client ID on Reconnect": If this box is checked, a random ID is appended when a new connection is attempted. This prevents (very likely) that two clients with the same ID are connected.
• "Publish Retain Flag": If this checkmark is activated, published values including the "Retain Flag" are sent.
• "Controller Subscribe": This topic is subscribed to by the controller. Commands can then be sent to ESPEasy via this topic, for example. You can also find information on this in the article ESPEasy - Execute commands and actions via HTTP, MQTT, UDP and directly.
• "Controller Publish": The topic under which sensor values are published (if activated) is defined here.
• "Controller LWT Topic": The MQTT server can report on the connection status of the client via the LWT (="Last Will/Testament").
• "LWT Connect / Disconnect Message": This option can be used to define the message that is sent via the LWT topic in the event of a connection or disconnection.
• "Send LWT to broker": Activates/deactivates the LWT functionality
• "Will Retain": Sets the "Retain Flag" for the messages sent via the LWT Topic.
• "Clean Session": Activates / deactivates a "clean session" login
• "Enabled": Activates / deactivates this controller

As soon as you have configured all the settings as you wish, you can apply the settings by clicking on "Submit".

After that your controller should be listed in the controller overview.

If you have configured more than one controller, you should remember the number of parts in which the MQTT server is configured. In this example the MQTT server is the first Controller.

To do this, first switch to the "Devices" tab by clicking on the "Devices" button.

If you have not already done so, you must first configure a sensor.

In this example the DHT11 is used.

To do this, click on the "Add" button in the first empty line in the "Devices" tab.

Then configure the option for "GPIO Data" and "Sensor model" according to your sensor.

But now to the MQTT part:
In order for ESPEasy to send the sensor data to the MQTT server, you must activate the checkbox in the "Send to Controller" section. Since you are sending the data to the first controller, the tick is listed next to the "1".

You can use the "Interval" option to specify how often the sensor is read out. The data is then sent at the same interval. In the example shown, the sensor value is read out every second and sent via MQTT.

Save these settings again by clicking on "Submit".

Back in the "Devices" tab, you can now also see the controller you have entered.

An external MQTT client can then also be used to check whether the data is being sent.

In the picture you can see a section of the "MQTT Explorer" view. This tool is free of charge and is very helpful when dealing with MQTT messages.

To do this, switch back to the "Devices" tab by clicking on the "Devices" button.

Then click on the "Add" button in the first empty line.

You will then be redirected to a drop-down menu. Select the "Generic - MQTT Import" entry here.

You can subscribe to up to four topics in the menu that then appears. Enter these under "MQTT Topic 1 - 4".

You can then define the names of the variables in the "Values" section. These variables will later contain the values received via MQTT. This is important, for example, if you want to react to these values using "Rules".

Once you have configured everything as desired, check again that you have checked the "Enabled" box and confirm the settings by clicking on "Submit".

Now you can react to the subscribed topics with the help of rules. To do this, you must first switch to the "Rules" tab.

If it is not visible, you have to activate it first.

Click on "Tools" to switch to the "Tools" tab.

Click on "Advanced" there...

...and check the "Rules" option.

Then confirm this setting by clicking on the "Submit" button.

The "Rules" tab should now be visible.

If not, it should be visible at the latest after a "reload" of the page.

On MQTT#Value_of_TestTopic1 do
if [MQTT#Value_of_TestTopic1]=1.00
pbani,5,150,0,0,0,0,0,
endif
endon

You can then enter the rules shown in the "Rules" tab, for example. These have the effect that every time the topic "Value_of_TestTopic1" a one is received, the command "pbani,5,150,0,0,0,0,0," is executed.

This command is part of the pxlBlck plugin. You can also find information about it here pxlBlck - Commands for configuring the pxlBlck