Publish to 2 mqtt topics with only an item

[rafa]

How could I publish to 2 topics with only one item. The objective is like on the image

I have a rollershutter and I would like to up and down with only that item and not to use 2 different items. Is it possible? How could I program it?

The item declaration (.item file):
Rollershutter Shutter_GF_Living “Living Room Shutter” (GF_Living) [“Blinds”] {channel=“mqtt:topic:LR_Shutter:LivingRoom_Shutter_Up”,channel=“mqtt:topic:LR_Shutter:LivingRoom_Shutter_Down”}

The mqtt generic things declaration (.things file):
Thing topic LR_Shutter_Up “LR_Shutter_Up” (mqtt:broker:mosquitto)
{
Channels:
Type rollershutter : LivingRoom_Shutter_Up “LivingRoom Shutter Up” [commandTopic=“out/A_Roller_Shades_1_Up/state”]
}
Thing topic LR_Shutter_Down “LR_Shutter_Down” (mqtt:broker:mosquitto)
{
Channels:
Type rollershutter : LivingRoom_Shutter_Down “LivingRoom Shutter Down” [commandTopic=“out/A_Roller_Shades_1_Down/state”]
}

[David_Graeff]

You can archive this with MQTT1. MQTT2 does not support this broken MQTT topic design though. An MQTT topic represents one state and that’s what MQTT2 supports

I recommend some additional logic on your µController to software emulate a
H-Bridge and have one MQTT topic only.

Cheers, David

[rlkoshak (Rich Koshak)]

One approach would be to define your Item as a Proxy item and trigger a rule to send the command to the right topic using the publishMQTT Action.

[rafa]

How could I do that? I don’t know

[rlkoshak (Rich Koshak)]

define your Item as a Proxy item

Design Pattern: Proxy Item

Please see Design Pattern: What is a Design Pattern and How Do I Use Them for information on what a DP is and how to use them. Problem Statement Often one faces one or more of the following situations: the need to perform additional logic before sending a command to a device the need to send a command to multiple devices based on a single event the need to do something different based on the state of one or more other Items the channel to update the state of an Item and the channel to send c…

trigger a rule

Rules

send the command to the right topic using the publishMQTT Action.

MQTT Generic Thing - Bindings

[rafa]

And in the case of a rollershutter, the received command is a number?

rule “Roller Shutter”
when
Item Shutter_GF_Living received command
then
if (receivedCommand == 100)
{
mqttActions.publishMQTT(“out/P_Prueba/state”,“ON”)
}
else (receivedCommand == 0)
{
mqttActions.publishMQTT(“out/P_Prueba/state”,“OFF”)
}
end

[rlkoshak (Rich Koshak)]

And in the case of a rollershutter, the received command is a number?

Not necessarily. As documented [here] (https://www.openhab.org/docs/concepts/items.html), Rollershutter can accept OnOff, IncreaseDecrease, and Percent as commands. But it stores is state only as a percent.

[rafa]

And how could I receive the same message from different topic? I mean, for example, I have 2 sensor, first “in/F_Garage_Door_Opened/state” send OPEN/CLOSE and second “in/F_Garage_Door_Closed/state” send OPEN/CLOSE too, but I’m only interested in the command OPEN from the two topic, and I would like to program a contact item that is OPEN when it is OPEN from “in/F_Garage_Door_Opened/state” and is CLOSE when it is OPEN from “in/F_Garage_Door_Closed/state”.

I tried this:
Mqtt thing:
Thing topic Garag_Contact “Garag_Contact” (mqtt:broker:mosquitto)
{
Channels:
Type contact : Garage_Contact_Opened “Garage Contact Opened” [stateTopic=“in/F_Garage_Door_Opened/state”]
Type contact : Garage_Contact_Closed “Garage Contact Closed” [stateTopic=“in/F_Garage_Door_Closed/state”]
}

Item:
Contact Garage_Contact “Garage Contact” (gGarage) [“GarageDoor”] {channel=“mqtt:topic:Garag_Contact:Garage_Contact_Opened”,channel=“mqtt:topic:Garag_Contact:Garage_Contact_Closed”}

Rule:
rule “Garage Contact”
when
Item Garage_Contact received update
then
if(Garage_Contact.state == OPEN)
{
Garage_Contact.postUpdate(CLOSED)
}
else
{
Garage_Contact.postUpdate(OPEN)
}
end

But doesn’t work

[rlkoshak (Rich Koshak)]

Please How to use code fences.

I would like to program a contact item that is OPEN when it is OPEN from “in/F_Garage_Door_Opened/state” and is CLOSE when it is OPEN from “in/F_Garage_Door_Closed/state”.

There is a bug in the binding right now that makes this not possible using just one Item. You need two separate Items , one for each topic, and a Rule to forward the new states to Garage_Contact which will become a proxy Item not linked to any Channels.