I'd upvote this twice if I could. Love to see efforts to /recycle/repurpose otherwise-useful hardware that has been abandoned by the manufacturer. I understand the commercial imperative to discontinue support for older hardware, but it still irks me no end.

What exactly does "will no longer be supported" mean?

Does it mean they'll stop working altogether?

Will they just not provide support for them but they'll keep working until the day they won't?

If it's the former, that's ridiculous and goes in the face of all the "good" they have been trying to do with the "leaf" program

"Dear Nest Learning Thermostat owner,

We want to make you aware of some upcoming changes that will impact our earliest generation thermostats, including those at Your House. Starting October 25, 2025, Google will no longer provide support for the Nest Learning Thermostat (1st gen) launched in 2011 and Nest Learning Thermostat (2nd gen) launched in 2012.

You will still be able to access temperature, mode, schedules, and settings directly on the thermostat – and existing schedules should continue to work uninterrupted. However, these thermostats will no longer receive software or security updates, will not have any Nest app or Home app controls, and will end support for other connected features like Home/Away Assist. See more details at our support website."

Upvoted. Anything that creates off ramps from the surveillance for advertising industry is great! Even tiny ones.

I hate to rain on a cool personal project but you could just get a cheap z-wave dumb thermostat like a CT101 for $50 and hook it up to home assistant.

Solves the problem permanently, no risk of future deprecations.

The CT101 looks awful compared to the nest thermostat. I don't think you are raining on a cool personal project.

Different folks different strokes. But I think saying "who cares what the decor inside the house looks like" is a little naive. Surely you can imagine that there is some population of people that care what the decor inside their house looks like AND do not want to hide the display on the thermostat? I think that group of people is probably a significant number of people... large enough that you are not raining on OP's parade.

I chose the CT101 based on low price, you could get a Honeywell T5 which is much more aesthetically pleasing and still supports Z-Wave, which accomplishes the goal of having a thermostat that won't lose smart home cloud support (by integrating it with Home Assistant using the standard Z-Wave protocol).

Plenty of cheap thermostats have good aesthetics. The $30 round Honeywell analog thermostat is a timeless design. Their $30 non-programmable digital thermostat (RTH5160) is aesthetically pleasing enough, I certainly wouldn't call it ugly. I didn't interpret the stated goal of this project to be particularly relevant to aesthetics.

Someone else replied about how ugly most cheap dumb Z-Wave thermostats are. Nests are beautiful by comparison. I've been searching for something I like as much aesthetically and come up short. That's one of the motivators

I love this idea. I don’t have a Nest, but I really appreciate you making an effort to keep these devices at least partially in service

What microcontroller would you use?

ESP32-C6 on the faceplate board to have the WiFi and Zigbee. STM32 on the "ring" portion - that drives the display and the scrolling ring