One homeowner built a smart house that keeps working without internet

A software developer says his house keeps running when the internet goes out. Spencer Kittleson has followed one rule for about ten years: nothing core in the house depends on a company's server. His write-up drew 262 points and 119 comments on Hacker News.

What he built

The important parts run on hardware he owns. Small Wi-Fi boards run Tasmota, a firmware he installs himself. An MQTT broker and Node-RED, two tools that pass messages and run automations, sit on a Raspberry Pi, a small low-cost computer.

He does use some cloud services, mostly Alexa and a few from AWS. But Alexa is treated as one more way to flip a switch. If it goes down, the wall switches and a wall dashboard still work.

What goes wrong with cloud-only gadgets

His Nest setup worked until Google broke the API, the connection it relied on. That is the kind of failure he now plans around.

He lists other examples from his talks:

• A Samsung fridge showing a TLS certificate error on its own screen
• A Camp Chef grill controller that needs Wi-Fi to show you the temperature
• Smart bulbs that force people to tape a wall switch on so the bulb keeps power

The trade-offs he weighs

He describes a triangle of choices. A cloud camera is cheap and convenient, but you pay with privacy. A switch he flashes himself takes more setup time, but he can connect it to anything. He decides where a device lands before it goes in the cart.

For the taped-switch problem, he prefers an in-wall Wi-Fi switch. The wall switch works the normal way, and he still gets a way to automate it. It takes more work to install than a smart plug. He also notes that he has broken his own rules many times and calls them guidelines.

He is clear that nobody needs this. He does it because he likes building things that work in the background.

What to do

Most people will not build their own system, and the post does not say they should. The useful part is the question. Before buying a smart device, ask what happens if the company's server or your internet is down. Check whether the device still works by hand, and whether it needs its own app and account to do its basic job.