Smartwatch app lets divers track one another underwater
Due to factors such as murky water and limited peripheral vision, it can be difficult for scuba divers to keep track of where their fellow divers are at all times. A newly developed smartwatch app, however, could soon make it much easier for them to do so.
Created by a team of scientists at the University of Washington, the software is designed to work with existing watertight third-party smartwatches such as the Garmin Descent and Apple Watch Ultra. It does not use GPS, since the required satellite signals do not travel well through water.
Instead, the app utilizes acoustic signals which are transmitted and received by the speaker and mic on each diver's watch. A minimum of three users are required, with one acting as the dive leader. Each person has to be located within a range of no more than 98 feet (30 m) of at least one other user.
The leader's watch regularly sends out acoustic query signals, which are received by the other divers' watches. After a fixed delay, each of those other watches sends back a timestamped response signal – those responses are received by both the leader's watch, and by those of all the other divers.
By analyzing how much time has elapsed between a response being sent by one watch and received by each of the others, it's possible to determine how far apart the divers are from one another, and in which lateral directions. Their vertical locations can also be ascertained if the watches are capable of measuring depth.
The technology has so far been tested in lakes and a swimming pool, where it was able to estimate divers' locations within a range of about 5 feet (1.5 m). It could even be combined with AquaApp, an acoustic messaging system previously developed by the same team.
"This and AquaApp can be used together," said doctoral student and team member Justin Chan. "For example, if the dive leader finds someone going the wrong way, the leader can send an alert: 'Hey, you’re going out of range. You need to come back.'"
Source: University of Washington