The Washington University engineers have developed an application that allows you to communicate underwater. Mobile communication at depths is not available for natural reasons, so the application works with sound waves, and it will be useful for both amateurs and professionals.
The water blocks the radio waves, so at the depth of just a few metres, mobile phones are losing connection. So, for example, submarines need a cable -- it also provides data transmission. But the sound waves in the aquatic environment are spreading perfectly, so scientists from the Mobile Intelligence Laboratory at the University of Washington, under the leadership of Tuochao Chen, a graduate student, chose sound rather than radio waves as the signal for AquaApp.
There is no need for complicated additional equipment: the application works perfectly with microphones and dynamics that are used on mobile phones and smart hours, so there will be enough waterproof case that can work at the right depth. Unfortunately, the only way to turn the signal into a sound wave is not enough for the system to operate, because the reception and transmission conditions are constantly changing depending on the distance between the two subscribers and other external circumstances. The signal can change significantly from the surface of the water, the bottom and the coastline, and the additional interference can be caused by waves, people and other objects. The authors have therefore had to adapt the system.
When initial contact is established between smartphones, a calibration signal shall be used that the two devices will be able to hear with a high probability. The receiving device shall measure its performance and inform the sender of the distortions so that it will adjust to a more stable wave under the given conditions.
During field trials on lakes and in the Gulf, the authors of the project were satisfied that their application was capable of providing reliable data exchange over 100 m, of course with a low bitrate, but of good quality enough to replace traditional gestures from divers. The AquaApp application is distributed free of charge: its source code is available on GitHub.