In the main system, a small 200-gm transponder (about the size of a matchbox) is placed under each car below the skidplate and behind a wheel. There is a receiver (antenna) at the start/finish line that will record the data transmitted by the transponder. The antennas are placed at right angles to the direction of travel of the cars. They cover the width of the track at each timing point.

Once the antenna receives the data, it will automatically process it to the central computer, where it is analysed and packaged for distribution to the various monitors around the track, the teams and to the television people. Twenty technicians monitor 20 cars simultaneously. Before the race begins, the technicians enter the car number of each driver into the computer in the order they will compete. They set the clock in the timing centre to the official time of day and start it running. When a car leaves the grid, an impulse travels to the central computer in the timing centre.

To perform these daunting tasks, about 18 tonnes of equipment (computers, laptops, GPRS and storage devices), 150 onsite monitors, 20 km of wiring and 19 antennas are embedded in the track. Data on the cars' speed and lap time is transmitted by the transponder in different frequency. The time taken to transmit the data, process it and get an output is less than .2 seconds.

Coming to the back-up system, this is placed in the timing tower amidst total security. The timing tower is generally built above the start and finish line to ensure good visibility. Time is measured through double infra-red photocells installed on the start-finish line. In case of a transponder failure in the car, the car identification is made manually. Computers then calculate the lap times and are able to provide ranking with `gaps' at any time. Digital high-speed cameras are also used to record all crossing on the finish line.

A car is timed in the pits too. About 11 sensors are used to detect when the cars arrive and how long they stop in the pits for tyre change, refuelling and whether they adhere to the reduced speed limit prescribed in the pit lane only. A speed limit of 80 km/hour is prescribed in the pits. If a driver exceeds the limit during a race, he is usually penalised with a time penalty. To avoid this, most teams have equipped their cars with a speed limiter that the driver has to activate (usually by pressing a button on the steering wheel) as he enters the pit lane. Another 22 sensors are used along the starting grid to detect false starts.

In 1965, Tag Heuer created the first miniaturised electronic time-keeping device, the Microtimer, which is capable of measuring time nearest to 1/1000th of a second.

In 1976, Tag Heuer came out with an innovative technology for time keeping — transponder technology. And that's when something called the automatic car identification timing system (ACIT) was introduced to meet the demands of Formula One and Le Mans 24-hour race.

Time is measured accurately to 1/1000th of a second though the system can measure time up to 1/10,000 for extra accuracy.

Picture by the author

partho@thehindu.co.in

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