Hello Everyone! 
I’m new to home assistant and still learning HA and YAML. I am not great at code and learn my own ADHD way, so sorry if this is a weird workaround. I’m adding this as I noticed a lot of people were struggling with it.
I wanted to set up automations around sleeping. I started with a simple time helper input which I added to my dashboard.
Example:
Wake Up: 8:00 AM
I then wanted to set up some automations for before going to bed.
Automation 1:
Check if the Living Room TV (android tv integration) is “on” 9 hours before my scheduled wake up time (08:00:00 AM) as set by the time helper. If “yes”, then send notification to Living TV saying “Go to bed”.
Automation 2:
Trigger 8 hours before wake time and see if Bedroom TV is “on” and if “yes” send notification to bedroom TV saying “Go to sleep”.
Here is how I got it to work:
-
Devices & Integrations > Helpers > Set up Time Helper Input
-
Using the File Editor Addon > Add to the configuration.yaml file the following:
sensor:
- platform: template
sensors:
bed_trigger_time:
friendly_name: "Bed Trigger Time"
device_class: timestamp
value_template: >
{% set wake_time = today_at(states('input_datetime.wake_time')) %}
{% set trigger_time = wake_time - timedelta(hours=9) %}
{% if trigger_time < now() %}
{% set trigger_time = trigger_time + timedelta(days=1) %}
{% endif %}
{{ trigger_time.isoformat() }}
**I noticed you need to specify “device_class:” with “timestamp” or the automation trigger date/time based on value of sensor won’t recognize and display your new sensor. (sensor.bed_trigger_time…)
- Set up your automation.
I hope this helps someone and please feel free to provide advice if there was a much simpler way to do this.