Over 2,500 runners, including top runners from around the world and celebrities ,participating in the half-and full-marathon on January 21, will have active Radio Frequency Identification chips wrapped around their ankles by a velcro belt (smart bands) to track their progress and record the time in which they complete the race.

The length of the marathon track makes it difficult to track the runners. In the past, there have even been scandals with racers appearing near the finish line out of the blue, without having run the entire race.

It's to avoid such incidents that some worldwide marathon events use RFID chips embedded in the shoes of the racers to track their progress.

The event organiser Procam International and Mika Timings GmbH have been working together since the conception of the Mumbai Marathon in 2004 and have been using a passive RFID chip, called Championchip, to track the runners. Last year, it was used by 1,700 runners.

However, with the prize money increasing with every passing marathon-over Rs 1 crore this time around-and the number of participants (a total of 30,000 this year), swelling each year, the organisers felt it was time to upgrade the chip. They will use AMB Activ, an active RFID chip, from this year onwards.

Frank Ratajczak, Project Leader, Mika Timings GmbH, said: "Since the data is automated, it allows us to instantly send the data to the broadcasting unit which then tells the viewers about the details and most importantly by the time the participant comes to collect the certificate, it is ready."

What's an active tag?

With passive RFIDs, antenna mats have to be placed at the starting line, every 5 km over the race course, and at the finish line to track each athlete's progress.

When a runner crosses a mat, his/her's RFID chip is read, and the identity, location, and split time are fed to the headquarters for uplinking or any other purpose. Active RFID chips do not need electromagnetic mats.

They have an internal long-life battery that switch on and off as athletes cross crosses over each start, split and finish line detection point. They automatically time dense packs of racers crossing/finishing at the same time. This also reduces their weight.

While the total equipment weight of Championchip tags was around 3,000 kg, AMB Active chips weighed only 800 kg, thus reducing freight costs too.