I made this up as an alternative to hefting hives to determine weights. It's a cheap luggage scale with a bit of home blacksmithing to hook under one side of the bottom board to give half weight. It takes about 10 seconds to weigh a hive and write the weight on top with a dry erase marker. Then I go round with my tablet and enter the weights into a Google Sheets file. It's not perfect, but I can get to within a couple of pounds, and it's a lot cheaper than what's next best.