Hi,

This comes under "I'm just curious".

At work, we have urinals that have these ZURN automated flush valves
on them. They have some kind of "electric eye" sensor, so that, after
a person leaves a urinal, the thing flushes by itself. The sensor
could also be proximity activated, but its pretty sophisticated, since
you can't just wave your hand over the "eye", and make it flush.
Something has to be the right distance from the "eye" for a certain
amount of time, or it won't activate. Pretty ingenious.

I've spent a lot of time contemplating how these things are powered.
There are no wires running to the valve assembly. There is a small
encasement, but not large enough to hold a substantial battery supply,
which, IMHO, would be necessary to power some kind of solenoid valve.

Does anyone know how these things work? It would give me something
else to think about when I'm at work.