Author Builds ESP32 Status Light With 10-Second Checks After Hours-Long Outage

Q: If your phone switches to cellular and your smart home keeps running, how would you know your internet died without an always-visible alert?

You often would not know right away. That is the point the writer exposed: if your smart home is built to run locally and your phone automatically falls back to cellular, the usual signs of an outage disappear. Lights, automations, and devices inside the home still work, while your phone keeps loading apps, so an ISP failure can go unnoticed for hours. An always-visible alert solves that gap better than a phone notification or a cloud-based warning, because those can be missed or fail during the same outage. The writer’s desk light continuously checks two things every 10 seconds: whether it can reach the router and whether the router can reach the wider internet. Its blink patterns make the difference clear at a glance: fast blinking means the local Wi‑Fi or router is unreachable, slow blinking means the home network is up but the internet is down, and solid means both are working. That matches standard troubleshooting advice. The key question in any outage is whether the problem is on one device, inside the home network, or with the ISP. Router and modem status lights, an Ethernet test, an ISP outage page, or tools like Downdetector can help answer that, but they require you to stop and check. A dedicated indicator removes that delay. So without an always-visible signal, you may not notice until a device that needs the internet fails. With one, you get immediate, local confirmation that separates Wi‑Fi trouble from a true ISP outage.

1 articles · Updated · How-To Geek · Jul 25

A tiny ESP32-based monitor now gives the author an always-on visual warning after a router update killed internet access overnight and the outage went unnoticed for about an hour.
Every 10 seconds, the device checks Wi-Fi first and then sends a small HTTP request to two well-known addresses to confirm internet connectivity.
Fast blinking signals the Wi-Fi link is down, while slow blinking shows the router is reachable but internet access has failed; a solid light means both are working.
The setup uses a Seeed Studio XIAO ESP32-C3 with ESPHome, took less than 10 minutes to deploy, and sits on the author's desk for quick checks when other services act up.