The specially designed bee passageway was
one of the key components of the bee detection system. Fig. 3
illustrates the top view, side view, and vertical view of the
bee passageway. Because the distance between the back and
abdomen of a honey bee was about 6 mm (Chen et al., 2012),
to ensure that only one bee could enter the passageway at
any given time, the diameter of each tunnel’s entrance was
set slightly bigger than 6 mm. The bee passageway combined
with a bee detecting module, and it was placed in the bottom
of the special-designed protective case. Moreover, two-paired
infrared transceivers were used to measure the frequencies of
honey bees’ entering and leaving the beehive. To guarantee
the counting accuracy, the align line of infrared transceivers
and the axis of the bee passageway were perpendicular to one
another.