An iroh powered smart fan

A DIY heat-wave gadget sparked cheers, eye-rolls, and one giant ‘why?’

TLDR: A developer showed off a do-it-yourself smart fan that works without a company cloud, using a tiny computer chip and a browser-based control page. Commenters were split between admiring the hack and roasting it as an absurdly complicated way to do something a cheap off-the-shelf gadget already handles.

A developer built a cloud-free smart fan using a tiny ESP32 chip, a temperature sensor, and iroh so it can be controlled from a simple website from anywhere in the world. On paper, it’s a neat summer project: no big company server in the middle, just your fan, your browser, and a lot of determination. But in the comments, the real temperature spike came from readers asking whether this was a clever hack or the most elaborate possible way to turn a fan on and off.

The loudest reaction was basically: “This is hilariously overbuilt.” One commenter boiled the whole thing down to the dead-simple action at the center of all this software drama: if it’s hot, turn the fan on; if not, turn it off. Another reader got stuck on the website side, wondering why the project used WebAssembly—basically a way to run app-like code in a browser—instead of a more ordinary browser setup. That sparked the classic internet side-eye: impressive, sure, but was all this machinery really necessary?

And then came the killer one-word review: “Why.” That pretty much set the tone. Others compared it to cheap store-bought smart-home gadgets that already control fans with voice commands, making this feel less like a practical purchase and more like a glorious hobbyist flex. The vibe was a mix of admiration, confusion, and heat-wave delirium: cool project, scorching debate.

Key Points

  • The article presents a cloud-free smart fan example built with iroh and an ESP32 that measures temperature and controls a fan.
  • It extends prior iroh ESP32 echo examples into a more practical sensor-and-actuator use case.
  • An ESP32-WROVER devkit with 4 MiB of PSRAM is recommended to support full iroh networking features, including relay-based remote access.
  • Alternative hardware options mentioned include the M5StickC-Plus2 and ESP32-S3 boards with PSRAM, while non-PSRAM ESP32 boards require relay disabling and QUIC buffer tuning.
  • The setup uses separate Rust projects for the ESP32 server and desktop client, and flashing is done via cargo/espflash with Wi-Fi credentials provided through an environment variable.

Hottest takes

"it comes down to: let _ = if fan_on { fan.set_high() } else { fan.set_low() };" — shermantanktop
"Why." — Teknomadix
"Someone with too much time on their hands" — Alien1Being
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