Track Supply of Specific Things in Home Assistant

This integration is for tracking specific items in your household.

• The component is added once for each item (e.g., dishwasher tabs)
• Each item is represented as a service/device and offers multiple entities
• Supply: How many pieces of the item we have left (entity type number)
• Morning/Noon/Evening/Night: How many pieces are regularly consumed (settable in steps of 0.25)? (four entities of type number)
• Empty: When do we predict the supply to be empty? (sensor of device class timestamp)
• Soon empty: Do we have to act? (binary sensor of device class problem)
• The integration adds a service that can be called regularly (e.g., in the morning) or when specific things happen. This service reduces the number of items left by the specified amount (this should be run as an automation).

Use Cases

I have devloped this integration with two use cases in mind:

• Track medicine for our dog. Unfortunately, our dog Bona is pretty sick, which means we have to regularly feed her several pills. The integration service is called every morning and evening, and we get a prediction on when it is time to get new supplies.

• Track dishwasher tabs. Every time the dishwasher starts (tracked via power consumption), our supply of dishwasher tabs is reduced by one. To predict when we run out, we assume that we run it 0.5 times every day.

Installation

This integration is easiest to install via HACS. At this moment, you'll have to add https://github.com/nilsreiter/ha-inventory-manager as a custom repository though. To do this, follow this guide.

Description

The integration provides several entities to track the state and supply levels of things. For each thing, the component stores the number of things we have, together with the prescribed use in the morning, at noon, in the evening and at night. Based on this information, the component predicts when we run out -- this is the state of the main sensor. A second "problem sensor" can signal the need to buy new things before we run out (by default, the sensor signals a problem 10 days before we run out).

To make this really useful, the component adds a service call inventory_manager.consume, which can be called to signal that a certain amount of things has been consumed. This updates the supply levels of each consumed thing type.

service: inventory_manager.consume
data:
  amount: 1
target:
  entity_id: number.dishwasher_tab_supply

It is also possible to consume multiple things at once, and for each thing we consume the predefined amount of things (i.e. if 0.5 pills of one type and 1.5 pills of another type has to be taken):

service: inventory_manager.consume
data:
  predefined-amount: evening
target:
  entity_id:
    - number.vetmedin_5mg_supply
    - number.vetoryl_30mg_supply

Back story

This is Bona, our 12 year old dog. Bona is an awesome dog, but unfortunately not very healthy. Thus, we feed her an increasing set of tablets every morning and every evening. Shortly after having started with Home Assistant, I started playing around with ways to track the inventory of Bonas tablets -- in order to timely get new tablets when the old packages get empty.

This essentially can be done with template entities, but it's cumbersome.

- unique_id: pills_vetoryl_10mg_daily
  state: >-
    {{ states('input_number.bona_pill_vetoryl10_pro_tag_morgens')|float + states('input_number.bona_pill_vetoryl10_pro_tag_mittags')|float + states('input_number.bona_pill_vetoryl10_pro_tag_abends')|float }}
- unique_id: pills_vetoryl_10mg_vorrat
  device_class: timestamp
  state: >-
    {% from 'bona_pills.jinja' import predict_pills_state %}
    {{ predict_pills_state("input_number.bona_pill_vetoryl10", "sensor.template_pills_vetoryl_10mg_daily") }}
  attributes:
    remaining_days: >-
      {% from 'bona_pills.jinja' import predict_pills_remaining_days %}
      {{ predict_pills_remaining_days("input_number.bona_pill_vetoryl10", "sensor.template_pills_vetoryl_10mg_daily") }}

This is an excerpt of my templates.yaml file, making use of custom templates, introduced in 2023.4. The first entity pills_vetoryl_10mg_daily calculates the total daily consumption of a specific tablet type, while the second pills_vetoryl_10mg_vorrat predicts when this pill type will be gone.

In addition to these two template entities (for no less than six different tablet types), this requires input_number entities for morning, evening and noon, because -- of course -- the dog gets a different combination of tablets every time (and this also changes from time to time).

Because this is very repetitive and makes all my files unreadable, I created this custom component (also, to find out if I could, and because it was fun).