A prototype watch been developed to prove the systems concept. It houses: a lithium ion battery, Xbee wireless
transceiver, LCD display and two buttons to select the team in question. The Xbee module is configured in
transparent mode to allow any wireless data packet received to be directly transferred to the serial LCD monitor.
Another Xbee is located in the ‘base station’ on the side of the field. Here a computer is fed with the wireless Xbee
data as well as player positions. Team selection is achieved by pressing one of two buttons located on the watch’s
top surface. These buttons determine the states of two Xbee pins. The corresponding pins of the Xbee located on
the sideline are directly governed by the state of the watch’s Xbee pins in a configuration known as I/O line
passing. When a button is pressed on the watch the base station can immediately begin to run the algorithm.