Where are you in the world? Like most datetime objects in HA, finishes_at value is stored as UTC timezone…
I copied your code with the change to my entity.
As an entity it works fine, but if I want to display it in the mushroom template card it tells me “unknown”.
What I’m doing wrong?
This is my template code I try to add the “Secondary”:
secondary: |-
{% if is_state("timer.boiler_timer", "active") -%}
{{ states('boiler_timer_countdown_remaining') }}
{%- else -%}
{%- endif %}
This is how it looks:
Should be sensor.boiler_timer_countdown_remaining
After reading this thread I found a different solution to display and control timers using mushroom and a couple of other custom cards. This method updates the time remaining every second.
I mostly use timers to control devices, for example a space heater and an electric blanket. Here’s how it looks:
Idle:
Active (timer running)
Active (not timed)
The required cards are stack-in-card, numberbox-card and timer-bar-card. I use them with a script which activates the correct device/timer and a separate automation to switch the devices off.
Here’s the code for horizontal version (edit: now with card_mod to center the numberbox card, it’s not needed when you change the mode to vertical):
type: custom:stack-in-card
mode: horizontal
cards:
- type: custom:mushroom-template-card
entity: switch.smart_plug_2_switch
icon: mdi:heat-wave
tap_action:
action: call-service
service: script.bed_warmer
data:
bed_side: switch.smart_plug_2_switch
timer: timer.heater
target: {}
icon_color: '{% if is_state(''switch.smart_plug_2_switch'',''on'')%}red{%else%}{%endif%}'
hold_action:
action: toggle
primary: Heater
secondary: '{{states(''switch.smart_plug_2_switch'')|title()}}'
- type: conditional
conditions:
- entity: switch.smart_plug_2_switch
state: 'off'
card:
type: custom:numberbox-card
entity: timer.heater
icon: false
name: false
service: timer.start
param: duration
state: duration
border: true
min: 0
max: 1800
step: 300
unit: time
card_mod:
style: |
ha-card {
margin-top: 10px
}
- type: conditional
conditions:
- entity: switch.smart_plug_2_switch
state: 'on'
- entity: timer.heater
state: active
card:
type: custom:timer-bar-card
entities:
- timer.heater
sync_issues: ignore
compressed: true
bar_radius: 4px
text_width: 40px
layout: full_row
bar_foreground: orange
icon: mdi:stop-circle
tap_action:
action: none
I can share the script too if someone’s interested.
8 Likes
Oh right. What a stupid mistake I made 
Thanks for noticing this! 
Yes please!
Glad you like it!
The script:
alias: Bed warmer
sequence:
- if:
- condition: template
value_template: |
{{is_state(bed_side,'on')}}
then:
- service: switch.turn_off
data: {}
target:
entity_id: "{{bed_side}}"
enabled: true
- service: timer.cancel
data: {}
target:
entity_id: "{{timer}}"
else:
- service: switch.turn_on
data: {}
target:
entity_id: "{{bed_side}}"
- service: timer.start
data: {}
target:
entity_id: "{{timer}}"
mode: parallel
icon: mdi:car-seat-heater
max: 5
Example script call:
action: call-service
service: script.bed_warmer
data:
bed_side: switch.smart_plug_2_switch
timer: timer.heater
And automation:
alias: Bed warmer - timer
description: ""
trigger:
- platform: event
event_type: timer.finished
event_data:
entity_id: timer.heater
id: Heater
condition: []
action:
- choose:
- conditions:
- condition: trigger
id: Heater
sequence:
- repeat:
until:
- condition: state
state: "off"
entity_id: switch.smart_plug_2_switch
sequence:
- service: switch.turn_off
data: {}
target:
entity_id: switch.smart_plug_2_switch
- delay:
hours: 0
minutes: 0
seconds: 5
milliseconds: 0
mode: parallel
max: 5
It’s separate to prevent reaching limit of parallel runs when handling multiple timers.
I use a while loop in the automation because I had some issues with zigbee plugs not reacting to a single command. If your devices are more reliable/less critical, you can do without it 
6 Likes
I have updated the card code from my post with a small card_mod entry which will center the numberbox card
3 Likes
Thanks @calisro and @Tsar for the above - Im an absolute beginner at this complexity of template and the above template has definistely got me into the ballpark of my use-case
I would like to ask though, if the timer is set to more than 24 hours this template only shows the hours remaining as timer-24 (eg: 36 hour timer shows 12:00:00)
How can this be alleviated to show the total hours (36:00:00)
This is awesome and exactly what I was looking for!! Thanks so much for sharing!
I hope this sort of functionality will be built in / simpler in Home Assistant someday… But for now this does it 
1 Like
Thanks so much for this code. I’m using it to display the time of my ‘rain delay’ timer for my irrigation system. It works great for that, but it would be just a little nicer if once it got to 0 I could then display a word like ‘idle’ or ‘off’ or something.
Is that possible?
{% set t = 'timer.kitchen_auto_off_timer' %}
{% set state = states(t) %}
{% set finish = state_attr(t, 'finishes_at') %}
{% set remain = state_attr(t, 'remaining') %}
{% set seconds = (as_timestamp(finish,0)-as_timestamp(now()))|int %}
{% set left = iif(finish == None,iif(remain == None,0,as_timedelta('0 ' ~remain).seconds),seconds) %}
{% if left == 0 %}
Off
{% else %}
{{ left| timestamp_custom('%H:%M:%S', 0) }}
{% endif %}
3 Likes
I am still not getting what am I missing to accomplish remaining time of timer to be shown in a for ex.: mushroom template card.
Current configuration:
- Configuration.yaml:
automation: !include automations.yaml
timer:
eldes:
duration: "00:10:00"
- automations.yaml:
- trigger:
- platform: time_pattern
seconds: "/1"
sensor:
- name: timer_eldes_remaining
state: >
{% set t = 'timer.eldes' %}
{% set state = states(t) %}
{% set finish = state_attr(t, 'finishes_at') %}
{% set remain = state_attr(t, 'remaining') %}
{% set seconds = (as_timestamp(finish,0)-as_timestamp(now()))|int %}
{% set left = iif(finish == None,iif(remain == None,0,as_timedelta('0 ' ~remain).seconds),seconds) %}
{{ left| timestamp_custom('%H:%M:%S', 0) }}
- lowelace:
type: custom:mushroom-template-card
primary: Remaining time
secondary: |-
{% if is_state("timer.eldes", "active") -%}
{{ states('sensor.timer_eldes_remaining', 'remaining') }}
{%- else -%}
{%- endif %}
Please help… Spent already 2 days on that… 
sensor.timer_eldes_remaining cannot even be found under entities.
Create the timer in the interface.
What you put in automations.yaml should actually be in template.yaml.
And this is how you get the info: {{ states(‘sensor.timer_eldes_remaining’) }}
I hope that makes sense.