Can you set up a Home Assistant MQTT switch like here?

Yes, this is one switch:

- name: "Prato 2"
  state_topic: "stat/sonoff-elettrovalvole2/POWER4"
  command_topic: "cmnd/sonoff-elettrovalvole2/POWER4"
  availability_topic: "tele/sonoff-elettrovalvole2/LWT"
  icon: mdi:water-pump
  qos: 1
  payload_on: "ON"
  payload_off: "OFF"
  payload_available: "Online"
  payload_not_available: "Offline"
  retain: false

But doesn't works with pulsetime. It's a simple switch. Pulsetime require the amount of seconds for the ON state.
The only way that I found is make an automation that track the irrigation unlimited sensor or change the irrigation unlimited code.

Hello,
have used an automation with state trigger and notify to set tasmota pulsetime. Using default of 15 min otherwise.

Automation:

alias: Relais Update Timer
description: Set relais timer, default to 15 min
trigger:
  - platform: state
    entity_id: binary_sensor.irrigation_unlimited_c1_z1
    to: "on"
condition: []
action:
  - variables:
      target: "{{'PulseTime'   state_attr( trigger.entity_id ,'relais')[1:]   ' ' }}"
      cmd: |-
        {% if state_attr( trigger.entity_id ,'current_duration') is none %}
          {{ target   '1000' }}
        {% else %}
          {% set t1 = state_attr( trigger.entity_id,  'current_duration') %}     
          {{ target   ( ( (t1.split(':')[0] | int *60   t1.split(':')[1] | int ) * 60 )   int(100) ) | string }}    
        {% endif %}
  - service: notify.gardenrelais
    data:
      message: "{{ cmd }}"
      title: Irrigation pulseTime update

Notify:

notify:
  - name: gardenrelais
    platform: rest
    resource: http://172.21.12.206/cm
    message_param_name: cmnd

Maybe this helps for a quick solution.

BR Alf

Hello, have used an automation with state trigger and notify to set tasmota pulsetime. Using default of 15 min otherwise.

Automation:

alias: Relais Update Timer
description: Set relais timer, default to 15 min
trigger:
  - platform: state
    entity_id: binary_sensor.irrigation_unlimited_c1_z1
    to: "on"
condition: []
action:
  - variables:
      target: "{{'PulseTime'   state_attr( trigger.entity_id ,'relais')[1:]   ' ' }}"
      cmd: |-
        {% if state_attr( trigger.entity_id ,'current_duration') is none %}
          {{ target   '1000' }}
        {% else %}
          {% set t1 = state_attr( trigger.entity_id,  'current_duration') %}     
          {{ target   ( ( (t1.split(':')[0] | int *60   t1.split(':')[1] | int ) * 60 )   int(100) ) | string }}    
        {% endif %}
  - service: notify.gardenrelais
    data:
      message: "{{ cmd }}"
      title: Irrigation pulseTime update

Notify:

notify:
  - name: gardenrelais
    platform: rest
    resource: http://172.21.12.206/cm
    message_param_name: cmnd

Maybe this helps for a quick solution.

BR Alf

Yes, this is the quickest solution, but I don't understand why the notify.

Yes, this is the quickest solution, but I don't understand why the notify.

Because I want to notify Tasmota how long it should open the zone relais, so the watering is not running endless if the close command does not arrive ( or someone klicks in the relais controll manually, then it stops after 15 minutes ).
And the MQTT commands did not work reliable for me.

Yes, this is the quickest solution, but I don't understand why the notify.

Because I want to notify Tasmota how long it should open the zone relais, so the watering is not running endless if the close command does not arrive ( or someone klicks in the relais controll manually, then it stops after 15 minutes ). And the MQTT commands did not work reliable for me.

Okay, so it's the same thing of my code with mqtt.publish in the first message