One of the chemical pumps.

The entrance of our bi-directional bee counter. Fourteen portals open into the hive through a black plastic block mounted under the green roof. Each portal is fitted with an infra red emitter and two infra red detectors. By determining which detector is activated first, the computer software can distinguish incoming from outgoing bees. The entrance structure is designed to assure that virtually every bee passes through a counter in an upright position.

A 14 port- bidirectional bee counter.