[gray-b-gon:5] Quite a contraption ...

[Roy Sykes]

... and a true contraption it is, Larry.  I'm impressed.  Unlike
me, you're a software guy who's also great with hardware.

One [hardware-related] thought:  All the mast, prop, and
drive belt gizmos simply serve to convert linear energy
(from wind) to rotational.  What about the idea of a direct
wind turbine, with the blades on both sides of the drum?
If these windwheels were effective, it would simplify your
design.

[Ember]

The thing needs absurdly little power, so there's no benefit in
conserving energy or maximizing efficiency. I didn't realize until it
was in operation that it matters not a whit how fast the drum turns.
The only thing that matters is how many square inches of water-covered
mesh are exposed to the dry air. If the drum turns so fast that the
mesh is still wet when it descends again into the tray, and it
usually does, then it's clear that additional speed makes no
difference.

A related aspect that I like is that neatness doesn't count, except
for a couple of places like adjusting the bike wheels' ball bearings.
All the rest can be pretty sloppy. Do you want to spread the black-
plastic liner very neatly? Go ahead! Do the bike wheels wobble as
they turn? Yes, they probably do. Building one of these is a great
project for people who think making things takes a skill that they
don't have.

[Ember]

Roy, I misinterpreted your idea. Trying over: little power is needed
to turn the drum, but the gearing-down of about 20:1 in the drive belt
gives the propeller enough torque to turn the drum in light breezes.

On the other hand, I might be completely off base. Someone should
build an evapotron with nothing but a drum with blades on, and see how
it works.