makeuseof.com — Discovery (discovered via Homelab) — Tue, 18 Aug 2026 07:00:00 GMT
Summary
This MakeUseOf article describes how the author pairs NFC tags with Home Assistant to trigger complex multi-step automations, leveraging HA's registry-based "platform: tag" trigger, which fires based on tag IDs stored in Home Assistant rather than data written to the chip. In the bedroom, a single tap turns off all lights via an area ID (so newly added lights are automatically included), arms a custom climate control unit built from an ESP32 C3 Supermini with a DHT22 sensor and OLED display, and switches that unit's active room to the bedroom via a custom ESPHome service. A second tag on the author's desk wireless charger activates a daytime-restricted work mode that arms the climate device, sets the office as the active room, and adjusts light brightness and warmth based on the time of day, with lights automatically turning warmer after sundown for gaming or side projects. The author concludes that the combination of registry-based triggering, area-based targeting, and firmware-level extensibility demonstrates how NFC tags can turn Home Assistant into a genuine automation platform.
I've been running Home Assistant for well over a year now, and once I had all my smart devices ported over, including the ones I made myself, I thought I had seen everything Home Assistant had to offer. Custom dashboard, offline support for IoT devices, automations as detailed as you'd want — I had everything. But having a custom-made smart Home Assistant dashboard is one thing; supercharging it with NFC tags is another.
Most people think of NFC tags as a novelty — tap your phone, turn on a light, done. Home Assistant's tag integration, however, is more interesting than that because it works off a platform: tag trigger that matches against a tag ID already stored in HA's registry. This means that automations fire based on what HA already knows about the tag, not on whatever data happens to be physically written to the chip in that moment.
This also allows you to use one tag in many different ways. You create one NFC tag in the Home Assistant companion app, and you can use it as a link, or even a physical QR code without ever needing to put that data on an actual NFC tag. For anyone who's fumbled around with an NFC writer app trying to get the formatting exactly the way it should be, this is a massive relief.
One of the most complex automations running in my Home Assistant setup is my nighttime automation that does three things: turns off all lights in my bedroom, arms my custom climate control unit, and switches the active room on said unit to the bedroom.
That first action is a light.turn_off call, but instead of listing individual bulb entities, I pointed at the bedroom's area ID. This is a small change that pays off constantly, as any new bulb, lamp, or light strip I add to my bedroom is automatically swept into the shutdown without me touching the automation again. I don't have to remember to update an entity list every time I buy or create a new smart light source, which happens more often than I'd like to admit.
The second action turns on an input boolean I use as a gate for my bedroom's climate-hold logic hosted on a small climate control and entity control device I made using an ESP32 C3 Supermini, a DHT22 sensor, an OLED screen, and a few push buttons. The unit has a climate control toggle, and tapping the NFC tag automatically enables it without me having to do so from the device. Finally, the third action calls a custom ESPHome service which switches the display on my climate control unit to the bedroom's page.
You can have multiple NFC tags around the house and put them all to good use. I have a similar automation running in my office. My desk's wireless charger has an NFC tag that fires only if the phone is tapped on it during the daytime, triggering my work mode automation. This is similar to the bedroom automation in the sense that it arms my climate control device and sets the active room to my office, but it also gets the lights just right in terms of brightness and warmth to match the time of day the automation was fired on.
The automation then tracks the daylight and adjusts light warmth in my office accordingly. This means I can fire this automation at any point in the day and get the light just right without having to fiddle with dials or buttons.
And if I'm sitting down at my desk after sundown, chances are I'm going to play games or work on my side projects. Since this doesn't require any "focus" lighting, the lights automatically turn warmer so I can look at the half a dozen screens around me without straining my eyes.
Taken together, these automations show off almost everything that makes NFC tags in Home Assistant worth using: registry-based triggering that's forgiving of imperfect tag writes, area-based targeting that scales as your hardware changes, careful sequencing to avoid race conditions between automations, and firmware-level extensibility if you make your own smart devices using ESP32s.
It's a small, two-room use case, but the pattern — tap a tag, cascade through several coordinated actions, sync state across two different automation flows — is exactly that kind of thing that makes Home Assistant feel less like a smart home app and more like a real automation platform.
Original article: https://www.makeuseof.com/home-assistant-nfc-tags-automations-absurdly-powerful/ Source: makeuseof.com (discovery)