Meet SoFi The Robotic Fish "Spy"

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The Soft Robotic Fish ( Photo Credit: MIT.Edu)

With climate change and overfishing wreaking havoc on our oceans, it is becoming increasingly important for researchers to closely monitor our marine life. However, observing sea creatures up close is almost impossible since human presence scares the animals. Now, thanks to The Soft Robotic Fish, aka SoFi, researchers may not only be able to keep a close eye on the elusive creatures, but also uncover undersea secrets that have been eluding us for centuries.

Built by MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL), the snow white remote-controlled robot closely emulates real fish, complete with a flexible tail that flicks from side to side and two “fins.” Though not the first autonomous underwater vehicle (AUV) created to monitor the oceans, SoFi resolves many of the issues that have hindered the usefulness of previous robots.

SoFi taking images of coral reefs (Photo Credit:

AUV’s traditionally have had to be tethered to a boat because radio frequency communications do not work well underwater. To overcome the hurdle, CSAIL director Daniela Rus and her team used sound waves. The ultrasonic technology can travel greater distances allowing drivers, using a modified, waterproofed Super Nintendo controller, to pilot SoFi from up to 50 feet away. To ensure SoFi can freely move around the ocean and maneuver like a real fish, a hydraulic pump seamlessly transfers water from one balloon-like structure to the other through its soft rubber tail, while a controller fitted with a smartphone lithium polymer battery powers the robot through the ocean, unhindered by tethers or propellers. CSAIL Ph.D. candidate Robert Katzschmann, lead author of the study published in Science Robotics on March 12, says, “To our knowledge, this is the first robotic fish that can swim untethered in three dimensions for extended periods of time.”

Also limiting traditional AUV usefulness is the risk of collision. With an exterior made of silicone rubber and flexible plastic that keeps its inbuilt electronics dry, SoFi poses no such danger. “Collision avoidance often leads to inefficient motion, since the robot has to settle for a collision-free trajectory,” says Rus. “In contrast, a soft robot is not just more likely to survive a collision but could use it as information to inform a more efficient motion plan next time around.”

SoFi is remote-controlled by scuba diver (Photo Credit: MIT.Edu)

During test dives in Fiji’s Rainbow Reef, SoFi glided alongside the unsuspecting marine life at depths of 50 feet for up to 40 minutes at a time, capturing high-resolution photos and videos. Even more important, it was able to do so without causing any disturbance. The researchers say sometimes the fish would swim alongside the strange-looking robo-fish in curiosity, while at other times they appeared utterly oblivious of its existence.

While SoFi currently only records video, future versions will include sensors such as thermometers. The researchers also hope to make it more autonomous and envision a day when swarms of the soft robots, powered by solar cells, will follow fish around, allowing scientists to gain insights into schooling dynamics and monitor their population. “For us, this fish is magical," says Rus. "We imagine someday it might help us uncover more mysteries from the amazing underwater world that we know so little about."


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  1. Why is monitoring our marine life becoming increasingly important?
  2. Why is it difficult for humans to observe marine creatures?

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Why do you think fish are less scared of SoFi than a human diver?


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“The researchers also hope to make it more autonomous and envision a day when swarms of the soft robots, powered by solar cells, will follow fish around, allowing...

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  • lunaTuesday, September 4, 2018 at 12:41 pm
    when i saw this i thought it would be used to gather information on other countries, but i like the way its used underwater better,learning more about our enviornment is important to keep people heathy and safe, so SoFi is very helpful. this robot invention has probably already been thought of but the way they designed it is so creative and interesting.
    • mrmars06
      mrmars06Monday, September 3, 2018 at 7:16 am
      Spy on the Russians. XD
      • Animal LoverSunday, September 2, 2018 at 10:40 am
        i agree, InnOvatOr, what would happen if a shark ate SoFi? then SoFi would become SoFood ;) (get my joke?)
        • Inn0vat0rFriday, August 31, 2018 at 8:07 am
          This robotic fish is definitely very interesting. The concept of robotic animals has already been used, but, like other robots, SoFi seems like a great way for scientists to investigate fish, and possibly even other marine life. However, I have some questions: What if a bigger animal, like a shark, ate SoFi? Since SoFi can swim alongside other fish, it must be pretty real-looking. So if fish can mistake it for one of them, then what happens when a predator of the fish does the same? How long did it take to make this robot? If you want to eventually have lots of them out in the ocean studying fish, it may be helpful to have a way to mass-produce them. SoFi is definitely still very interesting as a robot. It would be cool to see more versions of it, as well as seeing lots of them. This robot will surely advance our understanding of the sea creatures.
          • UnicornThursday, August 30, 2018 at 6:20 pm
            Nice, I like the idea but I feel like there shouldn’t be people in the water looking and controlling the robotic fish
            • brandonc758
              brandonc758Thursday, August 30, 2018 at 8:29 am
              • brandonc758
                brandonc758Thursday, August 30, 2018 at 8:09 am
                • brandonc758
                  brandonc758Thursday, August 30, 2018 at 8:04 am
                  • LandonWednesday, August 29, 2018 at 1:02 pm
                    cool how do you make one?
                    • ammaWednesday, August 29, 2018 at 11:58 am
                      • brandonc758
                        brandonc758Thursday, August 30, 2018 at 8:23 am

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