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Comment by lillecarl | Hacker News Reader

Practical engineer in me screams: SIMPLIFY, SIMPLIFY, SIMPLIFY.

Just plug the washing machine into a smartplug and alert when power draw drops to idle for more than X minutes.

Our previous washing machine had a mechanical rotating switch, sort of like an egg timer, built into it. I seriously thought about just gluing a pair of metal bits onto it to make a physical connection when it was done, which would either do something clever like trigger a RasPi into sending me a text, or something stupid like physically triggering a doorbell chime.

Some models do have an end-of-cycle chime on one of the timer contacts.

Can confirm this is super easy. It has the additional advantage of monitoring power usage and it allows you to cut power if the leak sensor under it goes off

My washing machine also makes a stupid chime melody thing. A microphone that listens for it would also be a simple way to do it.

I would go for the "monitor a number" before "sound recognition", unless you're talking about just using an amplifier to bring the chime into the entire house.

I'd dump cut the mic and wire it to some input before actually trying to check for the sound. But it's probably inconvenient to get to and monitoring overall power draw would be easy.

Or a current sensing transformer around its power cord.

but where's the fun in that :P

True, we all find enjoyment in different things

The fun is that you can reuse the setup for a japanese toilet, monitor energy use and use the data to play applause sounds in the bathroom after use.

Pretty sure Japanese toilets support this use case natively.

They DO have extensive settings on the LCD on the back of the remote if you pull it off the wall...

Not all washing machine appliances are same, unfortunately

Does your machine run on petrol or manual labor? In that case, listen for an engine or someone complaining.

I'm certain 99% of washing machines are powered by electricity, and if you live in 120V town and need 3 phase you can monitor power using the magnetic field on one of 3 conductors.

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