The greenhouse vents example reminds me a lot of a float valve (or ballcock).It's a simple mechanism that used buoyancy to either open or close valves as water level changes in a container.<a href="https://en.wikipedia.org/wiki/Ballcock" rel="nofollow">https://en.wikipedia.org/wiki/Ballcock
alexpotato · · focus · HN ↗
It's a simple mechanism that used buoyancy to either open or close valves as water level changes in a container.
<a href="https://en.wikipedia.org/wiki/Ballcock" rel="nofollow">https://en.wikipedia.org/wiki/Ballcock