SvitloBot ESPHome: a power-outage notifier that's just an ESP board on a USB charger

SvitloBot ("light bot") is a Ukrainian service that posts to a Telegram channel when the power at a home goes off and comes back. This ESPHome firmware by Andrew J. Swan turns a small ESP32 or ESP8266 board into the sensor. There's no sensing circuit: you plug the board into a wall socket through an ordinary USB phone charger. While there's power, it boots, joins Wi-Fi and sends a heartbeat to the SvitloBot API about once a minute (every 55 s in the ready-made firmware; an optional interval package makes it adjustable if you build it yourself in ESPHome). When the power goes, the board switches off, the pings stop, and the service posts that the power has gone. The docs list its advantages over an old phone doing the same job: no battery to swell, the size of a matchbox, and low enough power for 24/7 use. Install it from the browser with the web installer, or build it from the ESPHome YAML. Create a channel bot through svitlobot.in.ua, copy the key it gives you for a smartphone, and paste it into the "SvitloBot Key" field in the device's web page. Firmware variants also exist for healthchecks.io and for any custom URL, and an optional ESP-NOW failover package can relay through another board. Home Assistant can adopt the device. Why now: on 30 Oct 2026 Ukrenergo said hourly outage schedules would apply in some regions on 31 October, for all categories of consumers, after massive Russian attacks on energy facilities (LB.ua). What it tells you: the service only hears the board while both the power and your internet connection are up, so a router or ISP outage looks the same as a power cut.