I always miss the ding (it's in the basement and very quiet), I'd probably do fine if it simply kept beeping every few minutes, I'd eventually hear one. But jus

I always miss the ding (it's in the basement and very quiet), I'd probably do fine if it simply kept beeping every few minutes, I'd eventually hear one. But just one, nah, not nearly enough. So, I put a magnetic sensor on the door and made a circuit that starts beeping when the door has been closed for an hour. Simple as that. Door open, machine not in use. Door closed for less than an hour, probably still running. After that, beep until I open the door. No need for anything networked, no subscription, no terms of service, just more beeping. (Same with the microwave. There's never a reason to leave cooked food in the microwave with the door closed for a long time, so it dings every few minutes until I open the door. My old microwave didn't do this, but my new one does. It's so simple, why can't they all have this?)