developers.home-assistant/docs/creating_components.md

layout	title
page	Creating components

Alright, you're ready to make your first component. AWESOME. Don't worry, we've tried hard to keep it as easy as possible.

Example component

Add hello_state: to your configuration.yaml file and create a file <config_dir>/custom_components/hello_state.py with the below code to test it locally.

DOMAIN = 'hello_state'

def setup(hass, config):
    hass.states.set('hello.world', 'Paulus')

    return True

For more examples, see the Custom Python Component Examples on our examples page.