Automating heating vents with openHAB, esp8266 and LEGO - Part 1; rationale

It's winter here in Melbourne, and it's a cold one. Combined with the fact that everyone is spending a lot more time at home than before, it's time to start optimising for comfort and efficiency...

I've shared my house's floorplan before on this blog, but this time here it is overlaid with the "schema" of the gas central-heating system, which sends hot air through underfloor ducts into the house through eight vents (or "registers" if you prefer) - shown as red squares:

Now some houses *might* have "zones" implemented, where certain areas of the house are on a physically separated section of ducting and can be addressed and controlled individually. This house is not one of those. I've shown the two *notional* zones we'd probably *like* to have in orange (living spaces) and green (sleeping areas). If you're wondering, we've been advised that for technical reasons related to our heating unit (aka furnace) and available space under the house, a zoned system is not practicable. In any case, it would probably be a bit coarse-grained anyway, as these days I'm working pretty-much 5-days-a-week at home, from the study - the room at the bottom-left of the floorplan.

As such, I would like to be able to control the specific vent in my study, opening and closing it as needed so that it's warm to work in, particularly in the mornings, but also not wasting warm air that is better off being routed to elsewhere in the house in the evenings and on weekends. Also, if the temperature in the study is warm enough, I'd like the vent to shut itself off. It sounds like the height of laziness, but it happens that this vent is located underneath a large couch, so it's actually a major pain to adjust it by hand.

Off-the-shelf "smart vent" solutions have been available for a number of years, from Flair and Keen but they are Not Cheap, don't have any openHAB binding support, don't have stock available and/or don't ship to me in Australia. So it's a roll-your-own situation...