At the request of some researchers and pollination specialists, the Hivemind Developers have been working away on a Hive Strength Monitor which allows beekeepers to monitor the brood temperature and humidity as well as the number of bees flying at the hive entrance.
The module has a clip which allows you to hook it over the bottom brood box above the entrance. There is a sensor “looking” down at the doorway and keeping count of bees flying in and out. There is also a flat finger that protrudes into the brood chamber and sits just on top of the frames. On the end of this finger is a temperature and humidity sensor housed in an assembly that the bees will not propolise (we tried nearly 72 different versions).
See the sort of information the monitor provides in the charts below. It has already prevented one of our hives getting chilled brood.
The module gives you the ability to check the relative strength of two or more adjacent hives. The top solid line is the brood temperature, the middle dotted line is the brood humidity, and bottom dashed line shows the number of bees flying in or out of the hive. The green hive is obviously a stronger colony in this case.
The hive strength monitor can also be used in conjunction with our existing hive scale for a complete picture (weight in red above, ambient temp in light blue, bottom dashed orange line is number of bees flying and top orange solid line is brood temp). In this case the colony was struggling to maintain the brood temperature (the top orange solid line) as the autumn nights began to get cold (this was in Christchurch, NZ) and so we added insulation and closed off the mesh bottom sooner than we would have otherwise. The hive then recovered and is fine.