This Ingenious LEGO ROV Submarine Relies on Clever Magnetic Couplings

Submersible vehicles — even unmanned robotic remotely operated vehicles (ROVs) — face many challenges that land-based vehicles aren’t subjected to. Two of the most obvious are the pressure from the weight of the water around the vehicle and the need to protect any electronics from that water. How those challenges are overcome depends on how much money is in the budget and the specific conditions that the vehicle will be subjected to. If the budget is low and those conditions aren’t any more extreme than a swimming pool, it turns out you can make a remarkably effective ROV using LEGO bricks and clever magnetic couplings.

This LEGO submarine was built by the Brick Experiment Channel on YouTube, which is focused entirely on LEGO projects. As any LEGO enthusiast knows, there are an amazing variety of bricks and even electronics available. Those electronics include motors and radio control (RC) transmitters and receivers. This submarine takes advantage of those to provide remote control and propulsion. As you can guess, the most challenging aspect of this build was keeping the electronic components dry. To accomplish that, all of the electronics were kept safely enclosed within a glass food storage container.

Like most other food storage containers, this one is airtight thanks to the silicone gasket on the plastic lid. To transmit power from the electric motors to the thrust propellers on the exterior of the vessel, the creator used ingenious magnetic couplings. Neodymium magnets attached to the motors pull on magnets attached to the propellers, which allows for power transmission without having to drill any holes in the hull of the submarine. After carefully adding ballast to achieve neutral buoyancy, the ROV was tested in a pool. It worked well until it reached the bottom of the pool, at which point the pressure caused the lid to flex inward, ultimately reduced the buoyancy and making it impossible for the ROV to move upwards. After adding some reinforcements to the lid, the LEGO submarine was working flawlessly — if a bit slowly.