For "I'm done" notification, I use relay with power metering - looking at the power pattern, home assistant can be set up for notification after x time when that graph drops to floor.

Exactly, that's also my setup. Works as a charm! The power meter is a zwave switch which sits between the socket and the washing machine.

Same here. I’m sitting here reading stuff about reporting time remaining and wondering why that matters? Isn’t the concern just when its done?

I got one of these: https://www.amazon.com/dp/B08LN3C7WK . Connected it to my HomeBridge server (all local), set up a push notification using when the energy drops below 5 watts (which happens about 1-2 minutes after the cycle ends).

I setup a power monitor that resets a 5 min timer every time the power usage goes over X. It would still be nice to have an idea of how much time is left - I've considered setting up a pi-camera to OCR the display.

Shelly has a few relays with power metering and they offer lots of local-first and open ways of communicating. I use one to control power to my 3d printer.

> unfortunately my washing machine does not have an API

I'd love to see the breakdown of who would prefer a network-connected washing machine with an API vs who would prefer a device that you have to operate with buttons and switches like a cave man.

I guess a time is near when we want our washing machines and dryers to operate at peak solar power. So some kind of (very, very preferably local) api would be nice.

Caveman here. I put the washing in and then set a countdown timer on my watch.

Would be interesting to intercept the network traffic going from the washer to the manufacturer’s web service. It’s possible the API is simple enough that you could sub in your own little server that accepts and tracks the status events.

Tangent, but how did you handle lighting for the camera? I'm intermittently working on something similar to read a gas meter, but am struggling to find a way of lighting the digits sufficiently, while not leaving reflections on plastic over the digits. I've tried Pi-controlled LEDs and a smart bulb, with little success, so far.

Try switching your spectrum. I bet that plastic is transparent in UV or Infrared and with some minor camera surgery, you could get some visible light filter in there.

Alternately, try some polarizing filters instead.

Try diffuse lighting - the classic option is a light pointing at a white shower curtain. That should cut down on the specular reflections.

Alternately, get yourself a movable light, a live view through the camera, and move the light around until you find a position that gives you a good image.