I have NO idea what I'll do with this, but ordered one anyway. Maybe someone else can use this jewel. A hall-effect sensor water turbine for under $3. Cool. erco's first purchase of 2018.
More info at https://www.gearbest.com/sensors/pp_009181886235.html
"When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."
- Pablo Picasso