A warning on every page when a Raspberry Pi isn't getting enough power

A Raspberry Pi on a weak power supply freezes, glitches and shows stray text along the edge of the screen, and nothing on the player said why. Left alone, a weak supply can also corrupt the memory card until the player stops starting up. From Anthias 2026.08.2, the web interface tells you when it's happening, with a banner at the top of every page, the Schedule page included.

The banner has 2 forms:

• "This player isn't getting enough power" while the voltage is too low right now.
• "This player briefly lost power" when it dropped earlier and is steady again. It says how many times that happened since the player last restarted, and how long ago the last one was.

Under "What to do", the first step is the official Raspberry Pi power supply for your model, which the banner calls the fix in almost every case. Then the cable that came with it, unplugging USB drives, hubs and keyboards powered by the player, and not running the player from a TV's USB socket or a phone charger.

You can't dismiss the banner, since a weak supply keeps damaging the card while it's ignored. It goes away once the player restarts with a supply that holds. When a storage warning shows as well, the power banner comes first, because a bad supply is one of the main reasons cards fail.

System Info has a new "Power supply" card with the same verdict, how many drops there have been since the last restart, and when the first and most recent were.

Which players show it

Raspberry Pi players: the Pi 2, Pi 3, Pi 4 and Pi 5 images, installed with the installer or through balena. Anthias reads the kernel's rpi_volt sensor under /sys/class/hwmon, which works from inside the containers, so it needs no host agent. On x86 and other boards that have no such sensor, the "Power supply" card says "Not monitored", and no banner appears.

The kernel wakes Anthias whenever the reading changes, and every page load reads the sensor again, so the banner is current when you open the page. On current Raspberry Pi kernels, vcgencmd get_throttled no longer keeps a record of earlier drops, so Anthias counts them itself. The count starts over at every reboot.

For developers

/api/v2/info has a new under_voltage object with supported, active, seen_since_boot, first_seen, last_seen and count. Check supported first: when it's false, the device has no sensor and the other fields carry no information. bin/collect_debug.sh saves the /api/v2/info response in the bundle as api-info.json, and also reads the sensor and the kernel's under-voltage messages directly, for a player too broken to answer.