Trying to run openhab2 timer but i have multiple problems

[rossko57]

Please use ‘code fences’ to post code in this forum.

@unevoljitelj

import org.openhab.model.script.actions.Timer

You don’t need that import in OH2; you must have looked at some quite old OH1 examples.

@unevoljitelj

…
then
var Timer kuhinja_timer
…

This creates a new variable to hold the timer handle every time the rule runs.
If you want a second run of the rule to do something about a timer started by an earlier run of the rule, don’t do that.
If you look at examples, you will see the timer handle variable being declared outside of any rule, so that it has an existence between repeat rule runs.
See " Simple Example: Timers Version "

Design Pattern: Motion Sensor Timer

Edit: Updates for OH 4 Please see Design Pattern: What is a Design Pattern and How Do I Use Them for details on how to use DPs. Problem Statement Many motion detectors only report ON when they detect motion but do not send a corresponding OFF after no motion has been detected after a period of time. In addition, often one wants to control a device like a light for a certain period after the last motion is seen, not after the motion sensor goes to OFF. Therefore one needs to keep a Contact OPEN…

@unevoljitelj

var String kuhinja = mqtt_topic_kuhinja_occupancy.state

Rules DSL is a loosely typed language.
kuhinja won’t be a string, it will be a state type object.
If you want a string, it is easily got -

var kuhinja = mqtt_topic_kuhinja_occupancy.state.toString

@unevoljitelj

sendCommand(mqtt_homie300_test_air_output1,“OFF”)

If you use the sendCommand() Action like that, it requires you to supply two strings.

sendCommand("mqtt_homie300_test_air_output1", "OFF")

it’s generally preferable to use the method on the Item though

mqtt_homie300_test_air_output1.sendCommand("OFF") 
// or if this is a Switch type Item
mqtt_homie300_test_air_output1.sendCommand(OFF)