How to publish a Lovelace time picker helper to mqtt

Configuration Frontend
1

I have a time picker hacs on my lovelace dashboard and I like to publish the input value to a mqtt topic, each time the value is changed.
What is the most easy way to do that?

type: custom:time-picker-card
entity: input_datetime.visalarm1
hour_mode: 24
hour_step: 1
minute_step: 30
layout:
  hour_mode: double
  align_controls: center
  name: inside
hide:
  seconds: true
name: Vis Voeder tijd

So I like to send input_datetime.visalarm1 to the Mqtt topic vis/visalarm1