Home Assistant

This is an automated archive made by the Lemmit Bot.

The original was posted on /r/homeassistant by /u/Conscious-Draw-3759 on 2026-03-04 06:09:44+00:00.

Let’s break a classic taboo for a moment and talk about something that roughly half the population deals with sooner or later in life.

Yes. Periods. Bloody Periods. Now that we’ve survived saying the word on the internet, here’s the nerdy part:

As someone who is periodically betrayed by my own uterus, I had a thought recently.

Home Assistant tracks my lights, heating, energy usage, plants, vacuum cleaner, and trash pickup…

…but the one recurring biological phase that actually influences my comfort, temperature, mood, and survival strategy every month?

Nowhere in HA. Just a dedicated app on my smartphone. A closed system, safe but not very useful anywhere else. -- To be fair, it's a good tracker with a solid prediction method (I’ve been using it for a few years now).

Originally I just wanted an app-independent cycle tracker, mostly because cycle data is sensitive health data, and I really don’t like the idea of it being stored on someone else’s server.

And if I already have to endure the period every month, the data might as well help make things a little more comfortable.

Of course this escalated into a small custom component + Lovelace gauge card. The typical thing when starting to tinker ;-)

The idea is to expose cycle data as actual Home Assistant sensors, so the house can react to it.

Examples I'm experimenting with or more like my use cases so far:

• 🌡️ Trigger for Heating slightly higher on certain days because suddenly I'm freezing. Not always logical. Just Biological issue.
• 🕯️ Comfort mode → cozy lights, calmer atmosphere (because I get more light-sensitive and sometimes get migraine symptoms) - avoid this or at least minimize its, helps a lot.
• 🍫 Chocolate supply monitoring (a very critical system requirement ;-) ) – when the sweet cravings start…
• 🛒 Preparedness automation — automatically adding chocolate and menstrual hygiene products to my shopping list before the predicted start date (being prepared is much nicer)
• 😅 Optional “maybe be extra nice today” awareness automation for other people in the household (sorry, sometimes I get moody and socially overwhelmed)

That’s the automation side. Now for the visualization.

normal card view

click a day to set/delete a cycle start date

(example screenshot is in german, but the custom card uses the HomeAssistant system language*)*

The UI is a circular monthly gauge, intentionally subtle so it just looks like some mysterious dashboard dial. Not giving away much. but if you are aware of the color coding its easy:

🟡 fertile window || 🔴 predicted period + typical duration; the number in the center is the days_until_next_start

There are automations to add/delete period_start_dates, but you can also simply click the "remaining days"-number inside the gauge, which opens the calendar view.

For the nerds who like data structures, the sensor currently exposes something like this:

sensor.menstruation_gauge: [
history:
  - 2025-10-22,   
  - 2025-11-18,
  - 2025-12-17
  - 2026-01-14
  - 2026-02-14
next_predicted_start: 2026-03-15
days_until_next_start: 11
avg_cycle_days: 29
period_duration_days: 5
fertile_window_start: 2026-02-24
fertile_window_end: 2026-03-02
]

The prediction is intentionally flexible and based on the average of the most recent cycles, so it adapts over time instead of assuming a fixed rhythm. Much nicer for building automations on top of it.

So the goal is basically to make cycle data a first-class automation input in Home Assistant, instead of something locked inside an app or hosting sensitive health information somewhere else.

I have a working version running locally now. If there’s interest I’ll clean it up and publish the custom component + Lovelace card on GitHub.

So I'm curious:

What automation would other bleeding nerds build around this? Or what would partners of those come up with?

Because if our houses can react to sunrise, humidity and electricity prices… it can probably handle uterus-driven chaos too.

Cheers.

Edit:

Uploaded it to github and the steps i used to manually install:

https://github.com/nremey/HA/_menstrual/_gauge

Have fun, share, leave a comment in the issue with new ideas.

Anyone who can explain slowly in detailed steps how to make an Integration or HACS card out of it? so the manually install isn't required? AI wasn't helpful for me. maybe -- probably i think to complicated.