Two 14-year-old Arizona schoolboys built robot to remove microplastics from water using LEGO, duct tape and pool noodles

What started as a school science project in the middle of Arizona’s Sonoran Desert has turned into an unusual attempt to tackle one of the world's growing environmental problems. Two 14-year-old students built a small robot designed to remove microplastics from waterways — using materials as ordinary as LEGO pieces, duct tape and pool noodles. Brandon Miranda and Adriel Magana, eighth-grade students at Harvest Preparatory Academy in Yuma, Arizona, spent about six months developing their invention, called MP Guard. The notebook-sized robot was designed to move across the surface of water and collect tiny plastic particles. During a demonstration in March 2025, the students placed the prototype in a small pool, where its skimmer moved through the water and collected particles.

14-year-old students develop robot to remove microplastics from waterways

The material was then trapped using a filter made from sustainable coconut-husk fibres. The students hope the technology can eventually be developed further and tested in an actual ocean environment. The project did not begin with the machine they eventually built. Miranda and Magana initially imagined a drone that could travel across the water and collect plastic. However, limited funding forced them to rethink the design. They eventually turned to a much simpler approach, experimenting with an oil filter, 3D-printed parts, duct tape, pool noodles and LEGO pieces. Some parts had to be redesigned repeatedly, with one 3D-printed ratchet reportedly taking as long as 12 hours to reproduce.

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Why are microplastics such a big problem?

The students were trying to address a problem that scientists and environmental agencies have been studying for years. According to the National Oceanic and Atmospheric Administration (NOAA), microplastics are plastic pieces smaller than 5 millimetres. The agency describes plastic as “the most prevalent type of marine debris” found in the ocean and Great Lakes. These particles can come from larger plastic objects breaking down, synthetic fibres, tyres and several other sources. Because of their tiny size, some microplastics can be difficult to detect and remove once they enter waterways. The US Environmental Protection Agency is also studying their potential effects. The EPA says its researchers are developing methods to understand how microplastics and even smaller nanoplastics could affect human health and aquatic life.

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A small robot tackling a very large challenge

For Miranda and Magana, the project was also an exercise in solving problems rather than simply building a machine. When they struggled with the design, they received guidance from Arizona State University environmental scientist Vernon Morris. He helped the students work through some of the technical challenges while encouraging them to think about real-world environmental problems. The prototype was later demonstrated to nearly 100 students, teachers and others at the school. Miranda described the invention as “revolutionary”, while Magana said he was surprised that an idea that initially seemed impossible had eventually worked after several trials.

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What happens next?

The students' invention is still a prototype, so it is too early to know how effectively it could operate in large waterways or the open ocean. Scaling up the design, improving filtration and testing its performance outside a controlled setting would be major challenges. Still, the project highlights how environmental problems can become starting points for young inventors.

For two school students in landlocked Yuma, the ocean may seem far away. But their experiment shows that the next generation of environmental solutions could begin in an ordinary classroom with a simple question, a few inexpensive materials and the willingness to keep rebuilding when the first idea fails.