What are the devices in the Olympic swimming pool that look like screens facing the swimmers close to the far (left) end of the pool?Heidi Cool:
For some of the long distance events they are using Omega lap counters. These screens on the bottom of the pool at the end opposite the finish display the lap count to swimmers. The Rio 2016 website has a photo. They look like underwater TV screens.
If you are thinking of the squares on the wall at the finish, you might be referring to the touchpads. These are used for automatic timing. When the swimmer touches the pad at the end of the race it stops the clock. "How Do Swimming Touch Pads Work?" explains this more. You can also see them at the end of this video at the U.S. trials.
Timekeeping at Rio 2016 has further information.
You can also see more photos of the lap counters and touchpad timers on the Omega site at OMEGA Watches: Planet OMEGA.
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