I have a new idea - use a mains plug with a neon indicator to power the “power bank”. Use a light dependent resistor (LDR) (or phototransistor) to “look” at that neon. If it goes off we know the mains has failed. The LDR with suitable resistors signals high or low to the GPIO on the pi. No other PSU or buck converter needed.
Statistics: Posted by neilgl — Wed Jul 31, 2024 12:50 pm