Specifications

2.1. ANIMAL DETECTION AND IDENTIFICATION
Figure 2.1: Existing system: Overview
The second infra-red beam is interrupted as the bird leaves the gate. This
second trigger resets the system ready to scan for the next bird. Based on
the order of the beam triggering, the system can determine the direction that
the bird was moving (landwards or seawards).
The following problem has been identified on this system: if a second
bird enters the gate before the first one has exited, the system assumes it is
a double-trigger of the first bird and ignores the trigger. Thus, the second
bird’s movement is not recorded. When the first bird leaves the gate, it
is correctly recorded. However, when that second bird then exits the gate,
the system erroneously records a new animal entering the gate in the wrong
direction. The situation is only rectified after a timeout resets the system.
This condition undermines the purpose of the system: to accurately track
the times and directions of the birds’ movements.
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