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 b

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.