Timer.start TypeError: unsupported operand type(s) for +: 'datetime.datetime' and 'NoneType'

Configuration
1

I’m really struggling to get this timer to accept a number of minutes from a input_number slider. Any help most appreciated.

This is the full error I receive when invoking timer.start automation

unsupported operand type(s) for +: 'datetime.datetime' and 'NoneType'

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/websocket_api/commands.py", line 133, in handle_call_service
    connection.context(msg),
  File "/usr/src/homeassistant/homeassistant/core.py", line 1236, in async_call
    await asyncio.shield(self._execute_service(handler, service_call))
  File "/usr/src/homeassistant/homeassistant/core.py", line 1261, in _execute_service
    await handler.func(service_call)
  File "/usr/src/homeassistant/homeassistant/helpers/entity_component.py", line 213, in handle_service
    self._platforms.values(), func, call, service_name, required_features
  File "/usr/src/homeassistant/homeassistant/helpers/service.py", line 348, in entity_service_call
    future.result()  # pop exception if have
  File "/usr/src/homeassistant/homeassistant/helpers/service.py", line 370, in _handle_service_platform_call
    await getattr(entity, func)(**data)
  File "/usr/src/homeassistant/homeassistant/components/timer/__init__.py", line 175, in async_start
    self._end = start + self._duration
TypeError: unsupported operand type(s) for +: 'datetime.datetime' and 'NoneType'

my config

## hot water boost
input_number:
  boost:
    name: boost
    initial: 30
    min: 30
    max: 120
    step: 10
    mode: slider

timer:
  boost:
    name: boost


#### my automations
- alias: Timer start
  trigger:
     platform: state
     entity_id: input_boolean.boost
     to: 'on'
  action:
   - service: timer.start
     data_template:
      entity_id: timer.boost
      duration: "{{ states('input_number.boost') | int * 60}}"


#   - service: switch.turn_on
#     entity_id: switch.water_boost_timer_switch_switch

- alias: Timer cancel
  trigger:
     platform: state
     entity_id: switch.water_boost_timer_switch_switch
     to: 'off'
  action:
     entity_id: timer.boost
     service: timer.cancel


- alias: Timer stop
  trigger:
     platform: event
     event_type: timer.finished
     event_data:
       entity_id: timer.boost
  action:
    entity_id: switch.water_boost_timer_switch_switch
    service: switch.turn_off
2

Are you sure that error message is from the service call of the automation? It looks more like you tried to call the timer.start service from the Developer Tools.

I don’t see anything wrong with the automation. What version of HA are you running?

3

I click start on the timer in the UI and thats the error that is shown bottom.

Home Assistant 0.102.1
on Ubuntu, in Docker HASSIO

4

If I use the imput_boolean.boost to start the timer it works, then the UI works to start and stop. If I think on a restart if i just open the timer in the UI and click start its throwing that error so my guess is some initial value isn’t set

5

Ah, didn’t know you could do that. That must be a relatively new feature.

Yes, I believe this is because you haven’t set the duration in the config.

EDIT: I’d say this is a bug. The default duration is supposed to be zero. Although that’s not very useful of a value, not specifying a value for duration in the config should not cause the (new) START button to cause an exception. You might want to log an issue.

6

I’ve added duration: 1800 and thats fixed the timer. i’ll adjust my automation to not need the input_boolen to start as I can use the timer UI instead. Sorry I seem to have confused myself chopping and changing code. I do find this YAML a struggle at times lol

Thanks for your help :smiley: