Olympic timer Omega has created a lighting system to immediately inform spectators inside the Aquatics Centre who has won gold, silver and bronze.
It's one red dot for gold, two for silver and three for bronze.
The small lights line both sides of the diving boards.
"The viewers on TV can see at home immediately who the winner is with their (results) superimposed on their lane, and now this way viewers inside the arena can also know without looking up at the scoreboard," Omega timing chief Peter Huerzeler said.
The timing system produces results down to the tenth of a thousandth — one decimal point further than the system used in Beijing four years ago.
However, swimming governing body FINA still only calculates results down to the hundredth. That means that if two swimmers tie, Omega will likely know who was faster.
"But we never say who won," Huerzeler said, recalling how French journalists were knocking on his door after Camille Lacourt and Jeremy Stravius shared gold in the 100-meter backstroke at last year's world championships in Shanghai.
"Everyone was asking me who won, but we won't say," Huerzeler said.
When Michael Phelps edged Milorad Cavic in the 100 butterfly in Beijing for the closest call in his run to eight gold medals, Phelps' time was 50.58 seconds and Cavic's was 50.59.
"We can go to a millionth of a second, but it's up to the sport governing body," Huerzeler said Wednesday.
Use of the finishing touchpads was a deciding factor in the Phelps-Cavic race. While Phelps slapped both hands on the wall, Cavic glided in with his finger tips.
A minimum of 1.5 kilograms (3.31 pounds) of pressure is needed to activate the touchpads.
For close results, there are overhead cameras in the finish area which record 100 images per second.