homeassistant

Motion sensor or light switch.

There are so many variables at play here.

If it's an electric shower, you can do what a salamander pump does and add some detection wires on the shower box's on-switch. I appreciate you don't want wires around the shower but it's a fully direct "is the shower on" detector and the wires are technically in the shower rather than around it.

Your individual shower habits might be predictable enough to if than your way to it with existing sensors.

If you track current draw on your boiler / water heater that would indicate a draw on hot water during time when you typically shower. You can add other checks for it to pass if you find too many false positives.

If you’re as glued to your phone as every one else alive atm a simple rfid / wireless charger or something you set your phone on when you strip for the shower triggering the event will likely be the most straight forward approach unless you bring your phone in the shower lol I’m occasionally guilty if the podcast is good enough 😅

@batshit so ein Quatsch