Sure, put it out for free and I’ll donate the same as I do for any open source software I use.

I’m internet poisoned as hell but I’m surprised that that’s not common knowledge. Its also often 1488 with the 14 referring to the 14 words of the following neo-nazi slogans:

“We must secure the existence of our people and a future for white children”

“because the beauty of the White Aryan woman must not perish from the Earth.”

88 = Heil Hitler

Juice->Jews

They’re pretty standard parts so don’t feel like you need to go with Fantech in particular, feel a little like I accidentally shilled for them a bit, just happened to be on their website (AFAIK they do make good stuff though). Glad that it helped and best of luck :)

The switch would be something like this. I think differential pressure between the inside of the duct and your kitchen would work.

and any “normally closed” damper would work. Wired up such that when your range hood is switched on, it also switches the motor in the damper on so that it opens.

The simplest thing would be a pressure or airflow sensor hard-wired to the switch for the hood itself.

Also consider instead of a 1 way valve installing a damper that only opens when your range good is turned on.