Accurate time tracking has minimised finishing-line disputes in athletics and racing events
Sports have new controversies, mostly related to doping. But the older ones, those related to picking the winner in a tight race, are almost dead now. Technology, especially those used to measure time and distance, has been the game changer here.
Time tracking in athletics and all racing events has become enormously sophisticated and accurate.
Margins as close as a micro-second (a millionth of a second) can be easily metered. From the initial days of manual stopwatches, today, fully automatic timing, or FAT, has improved decision-making in sports to a great extent.
Deployment of the fully automatic time tracking techniques involves use of precise digital electronic circuits. So, how do these circuits get this precise?
The precision in electronic circuits comes at two levels — by meticulous computation and (as a precursor to perform such computation) in the form of ‘perfect synchronisation’ between individual modules making a complex circuit.
For instance, the microprocessor must write or read into memory locations at exact instants of time, and this can be accomplished only with a reliable reference signal. Synchronisation of different tasks, involving numerous steps in a complex circuit is a challenging task.
“Clock and time in a digital circuit are quite different from what we know of in real life. Any steadily varying electrical signal in a circuit can be used as a reference for synchronising different modules while executing complex programmes. This reference signal is considered as clock, and the count of these steady variations keep track of time. When used as timers, simple programmes translate these circuit metrics into the time we know in real world,” says Anil Kumar D., assistant professor at an engineering college in Bangalore, and an embedded systems enthusiast.
Like in wristwatches, most digital circuits use a crystal resonator to generate the synchronising signals, or the clock. A crystal resonator is capable of generating electrical signals from mechanical vibrations by a process called the piezoelectric effect. Quartz crystals are widely used to generate oscillations of very precise frequency.
For high-frequency applications, transistor circuit-based clocks are used. The consistency with which these internal clocks operate directly translate into the reliable timing results for all events they are deployed in. If all sports were to have finishers like sprinter Usain Bolt, with obvious margin of lead, the stringency on time-tracking could be relaxed because even manual stopwatches would do the job.
However, as most events lead to close finishes, using digital circuits for precise time-tracking is the best approach currently. Further, this approach also eliminates errors.
Finishing in style
Different technologies are employed for different sports today to meter the finish time. When the start gun is shot at track or swimming events, it automatically triggers a digital timer by sending an electromagnetic signal. This timer then stops with an accuracy of a hundredth or millionth of a second as need be, by using sensors at the finish line. For track events, the finish line has a laser beam across the track. When an athlete reach the finish line, the momentary outage of laser triggers the timer to stop, thereby, measuring the duration.
In events such as swimming, a slightly different approach is employed. The walls at the end of the pool have sensors on the touch pad. When athletes touch the sensor pad, an electrical signal is triggered to stop the timer.
In throwing events such as shot put, discus throw and javelin throw, it is not time but distance that needs to be measured precisely. Laser ranging, and in some cases wireless transmitters on the thrown implements, help in accurate distance measurement.
Even with all this data, contention over results do occur when circuits fail. For events such as long jump, triple jump and high jump, strip photography is used to judge an athlete’s performance. In this technique, high-resolution camera takes vertical images of the finish line at very small intervals. By comparing the images taken in sequence and analysing them, reliable decisions can be made.
Electromagnetic transmitters placed on every athlete can also be used to continuously relay information to the control room; this technique finds more widespread use in track events such as cycling and to very advanced levels in auto racing.