There are washing machines without anything more complex than a switch in them. If you really had a "pile of disassembled washing machines" you'd know that.

[–] Meowoem@sh.itjust.works 2 points 10 months ago

Nothing to control the motor, nothing to control the heater, nothing to do timing or turn on and off water in and out?

Even a really shitty one has door lock sensor, temperature sensor, turbidity sensor..

Which means logic gates and transformers and things to shift voltages or control power flow.

That's before you even get into the logic of controlled programs or advanced features like weight based energy saving.

A micro controller connected to a few relays and sensors could replace all the complex stuff and it'd cost far less, plus it could tell you which sensor is out. Plus it allows you to do otherwise very complex things like reprogram the current job while it's running or to sync with other devices to limit max power load.