This past weekend, we went camping at a local state park. (Thanks for the loan of your camper, Bro!)
I'd not been in the showerhouse of this park before, and I was a bit mystified by the sinks. I've seen faucets with handles, but when I turned the single knob at the sink, nothing happened. I tried another. An elderly lady (who was likely from out of the country, as she was speaking a different language) leans over and waves her hand under the faucet. Motion sensor. Figures it would take a foreigner to show the local how to use the sink. The knob was apparently supposed to control temperature, although that never proved to be the case. Perhaps someone else could enlighten me to the purpose of a knob on a motion sensor faucet?