A monitoring system for carbon dioxide and humidity in honeybee hives

Two of the most relevant gasses correlating to honeybee colony health are likely carbon dioxide and humidity. There are a wide variety of sensors on the market for monitoring these gasses, covering a range of different sizes, prices and accuracy. The most accurate carbon dioxide sensors, at an appropriate physical size for use in honeybee hives, are based on Non-Dispersive Infra-Red (NDIR) detectors. In this work we investigate the use of two of these sensors . As molecular diffusion will severely impact the local equilibrium of any gas measurement, we investigate the most appropriate placement of the sensors by positioning them in the comb of a frame in the brood box, above a modified crown board and in the queen excluder. Both sensors also inherently provide relative humidity and temperature data. Data logging was provided by Teensy 3.5 microcontroller circuits with a current consumption low enough to allow battery deployment if required. With a temporal resolution of less than a minute and several thousands of hours of data for comparison, we present the daily and long-term trends in these important gasses in multiple honeybee colonies.