Anyway, here is a rough (very) picture of my idea.
John Polk wrote:How about something as simple as a turbine vent.
The slightest breeze will operate it...but wait...there's more...
The venturi effect:
Hot air rises. With hot air rising through the duct, the vent will begin spinning, regardless of outdoor wind conditions.
I will have some things to try. I guess start with a pipe and try/add things... The turbine vent sounds simple. Start simple and before trying complex for sure.