Specifications

2.4. DATA DELIVERY

Markham modiﬁed this original system by replacing the desktop computer

with a microprocessor which logs the data in the its on-board non-volatile

“ﬂash” memory. Unfortunately, due to limited capacity, the birds’ entire

identiﬁcation number is not stored, but rather only an eight bit identiﬁer

and a lookup table. The total number of birds is thus limited to 256. The

time at which the bird passed through the gate is stored as the number

of seconds that has elapsed since the last upload in 16 bit integer format.

Another byte is used for status and direction storage. Thus, a total of four

bytes are required per data record.

2.4 Data Delivery

There is currently no remote uplink facility. Operators must periodically

physically connect to the device using an RS232 serial connection. This

data is downloaded to a portable computer and removed for analysis. The

memory is then erased and system time reset. The date and time at which the

system was reset must be recorded since the timestamps are relative, being

the number of s econds which have elapsed since the last upload. The system

is capable of storing approximately 13 000 such records (approximately one

month’s data).

The data is delivered in raw format in three columns: the time in seconds

which have elapsed since the last upload, ID of the bird and a status/direction

indication. It is delivered in raw hex format, requiring a trained operator to

import this data and convert it to a human-readable form.