As avid big game hunters in the west (Colorado) and numerous other states and provinces, we always struggled with effective means of determining wind drifts and thermals when there didn't seem to be any wind at all. We used various devices for years to determine wind direction but found nothing fit the bill. Puffers, lighters, thread, and other means of identifying wind drifts and thermals didn't work in the dark or were so small we were constantly losing them.
So we set out to develop a science based approach to building a product that would work in the dark and daylight, was super accurate in identifying wind direction even during periods of low/no wind. We spend (too much) money on developing this thing and even filed a patent.
We don't have any illusions that every hunter will require the use of a "gadget" like this every day and you may even find this idea "way out there" but I'm curious what you guys think.