Setting a variable to a value based on sensor state

Configuration
1

Anyone able to assist with updating a template sensor based on a binary sensors value?

I want to set a sensor that tells me when last a door was opened. i.e. When my front door opens - set the value of the template sensor to that date.time - but - it must not get updated again when the door closes. So : TEMPLATE_SENSOR = WHEN DOOR_STATUS = OPEN THEN DOOR_STATUS.LAST_UPDATED.

2

You can use the Input Text component for this.
Thereā€™s also an automation example in the docs.