Shutdown safely if power fails using GPIO input

[n2mfc]

I am new to the under-the-hood workings of Home Assistant. I want to be able to shut down HA gracefully after a period of time if a power failure is detected. The Pi will be connected to a UPS. I do this on some of my other Pi projects by running a Python script that monitors a GPIO pin that is connected to a 3V source not powered by the UPS the Pi is plugged into.

So I would like to be able to monitor power by reading the GPIO input going low, poll it a couple of minutes after the power failure is detected to make sure it is not just a temporary glitch, and initiate a graceful shutdown if the AC power is still out. I have at least 5 minutes of UPS power to rely on.

In a full Rasbian install this is easily done, but I don’t see how to do it in a HA install. I did see some old posts but they pointed me to GPIO features in HA that were deprecated. Is there a way to do this and are there any articles that anyone could point me to?

Thanks in advance.

Danno

[tom_l]

GPIO support is now via a third party integration. This recent post should put you on the right track:

Pysical pushbutton on GPIO to shut down Home Assistant?

You don’t have much access to the host OS to do that. It would be much better done from within HA. You can call the shut-down service from an automation, service: hassio.host_shutdown. The way you trigger that automation to be convenient and rapid is up to you but some ideas: A simple ESPHome button. A button on an existing device you have (long press to guard against accidental activation). A GPIO button, you will need this: GitHub - thecode/ha-rpi_gpio: Home Assistant Raspberry Pi GPIO Inte…

In your case a mains relay could switch 3.3v on the GPIO to trigger your automation.