For acoustic-based networking and communication underwater, researchers have created AquaApp, a mobile app that can be used with already-existing gadgets like smartphones and smartwatches.
Hand signals are the sole way for the millions of individuals who partake in activities like snorkeling and scuba diving each year to convey safety and navigational information underwater. Professional divers can use more than 200 signals in their vocabulary, although recreational divers may only use around 20. These signals can be used to show anything from the amount of oxygen in the water to the presence of animals in the area to the completion of group tasks.
These hand signals’ visual character makes them less effective at a distance and in low light. Two-way text messaging could be used as a replacement, but it requires expensive, specialized technology that isn’t easy to get.
University of Washington researchers demonstrate how to enable underwater texting on the billions of smartphones and smartwatches currently in use using only software. The group made AquaApp, which is the first smartphone app for networking and talking underwater using sound waves. It can be used with modern devices like smartphones and smartwatches.
At SIGCOMM 2022, the researchers’ paper outlining AquaApp was delivered on August 25.
“For wireless connection, smartphones rely on radio signals like WiFi and Bluetooth. While acoustic signals operate well underwater, those don’t, “Tuochao Chen, a UW PhD student in the Paul G. Allen School of Computer Science & Engineering and a co-lead author, said. “We demonstrate underwater communicating with AquaApp using the speaker and microphone that are commonly found on smartphones and watches. “People simply need a waterproof phone cover rated for the depth of their dive, aside from installing an app on their phone.”
The 20 most popular signals are prominently displayed for quick access, and users can choose from a list of 240 pre-set messages that correlate to the hand signals used by professional divers. Also, users can sort messages into one of eight different categories, such as the status of equipment, the weather, or directions.
When making the software, the team ran into some technical problems that they had never seen on dry land.
In comparison to applications over the air, the underwater environment raises additional issues, according to co-lead author and doctoral student Justin Chan from the Allen School. For instance, changes in signal strength are made worse by surface, floor, and shoreline reflections. The movement of people, waves, and objects nearby can disrupt data transmission. Additionally, different smartphone models have distinct features for microphones and speakers. To guarantee AquaApp would function in actual usage scenarios, we had to make quick adjustments in response to these and other circumstances.
The propensity of devices to quickly change location and closeness to the current and the varied noise profiles the app might experience as a result of the presence of vessels, animals, and even low-flying airplanes were further problems that needed to be addressed.
The group made an algorithm that lets AquaApp change the bitrate and acoustic frequencies of each transmission in real time based on factors like distance, noise, and differences in how devices respond to different frequencies.
This is how it goes: an app first sends a brief note, known as a preamble, to the recipient device when a user wants to send a message to that device. The algorithm is conducted by AquaApp on the second device to find the ideal circumstances for receiving the preamble. The first device is then instructed to send the message under those parameters.
In order to facilitate messages between various devices, the researchers created a networking protocol to share access to the underwater network, much like how WiFi networks regulate internet traffic. AquaApp’s local network may support up to 60 different users concurrently.
At six different sites, including under a bridge in calm water, at a well-liked waterfront park with strong currents, close to the fishing dock of a busy lake, and in a bay with powerful waves, the team examined the practical utility of the AquaApp system. The performance of the app was assessed by the researchers at depths and distances of up to 12 meters and 113 meters, respectively.
According to our tests, the best underwater communication range is up to 30 meters and 100 meters for SoS beacon transmission, according to Chen. These qualities ought to be adequate for the majority of leisure and work-related situations.
The system was continuously ran on two Samsung Galaxy S9 smartphones by the researchers while the screens were turned on and the system’s maximum volume was on. This allowed them to assess AquaApp’s effect on battery life. Over the course of four hours, the software only reduced the smartphones’ battery power by 32%, which is within the maximum suggested dive time for recreational scuba diving.
According to the senior author and UW professor in the Allen School, Shyam Gollakota, “AquaApp delivers underwater communication to the public.” “The current status of underwater networking is comparable to the 1970s ARPANET, the internet’s forerunner,” when only a select few had access to it. By democratizing undersea technology and making it as simple as downloading software on your smartphone, AquaApp has the ability to alter the status quo.
The AquaApp website hosts the team’s data and open-source Android code.
The National Science Foundation and the Moore Inventor Fellowship both provide funding for the researchers.
