Better Fresh Air Venting Plan

[craigwmiller]

Okay, I have a dream, google is letting me down finding an off-the-shelf product to satisfy my dream and I'm asking here to see if someone has seen such a product before I just make it.

I want to have a exhaust fan controlled by 2 (two) humidistats. One inside, one outside. If the humidity inside is above the proper threshold AND higher than outside, the fan is allowed to run; if the humidity is higher outside than inside, it's not allowed to run (regardless of the humidity inside).

The fan can be switched on/off via a power switch, a/c, d/c, relay, I care not - the logic is all I'm after at this point... The logic is something I'm capable of doing but truly I'd just rather give someone else my money so I can enjoy a few beverages with the time I would put into scheming (not to say that the scheming time wouldn't involve some beverages, but you get the idea)


Anyone run across such a device (or already-designed-schematic for such a device)?