Jared Lepora spent months puzzling over tendon routing. The 16-year-old from Bristol was trying to build a robotic hand that could actually grip things — using nothing but LEGOs.
In October, he presented his finished design at a major robotics conference in Hangzhou, China. The hand works. It grasps objects. And it's made from a toy.
How a teenager reverse-engineered a research prototype
Jared started with an existing design: SoftHand-A, a sophisticated 3D-printed robotic hand developed by researchers. His challenge was to recreate it using LEGO MINDSTORMS, a robotics kit that's been around for years but rarely pushed to this level of complexity.
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Start Your News DetoxThe hand has two motors and four fingers. Each finger contains two tendons — essentially strings that pull to make the joints bend. When you pull the tendons, the fingers flex. When you release them, they extend. Simple in principle. Nightmarish in execution.
"The hardest part was the tendon routing around the rotating bearings," Jared explains. Those bearings — over 100 of them — had to sit precisely enough that the fingers could move smoothly without jamming. One misaligned piece and the whole hand would lock up.
What makes this remarkable isn't just that he built it. It's that the LEGO version performs nearly as well as the original 3D-printed prototype. Yes, it's slightly slower and can't handle quite as much force. But for something assembled from plastic bricks, it's genuinely capable.
Jared co-authored a research paper on the project with his father, Nathan Lepora, a robotics professor at the University of Bristol. The paper, published on arXiv, argues that this design could do something the original couldn't: inspire the next generation.
"Since the hand can be constructed from LEGO pieces and uses state-of-the-art design concepts for robotic hands, it has the potential to educate and inspire children to learn about the frontiers of modern robotics," they write.
That's not just nice sentiment. Jared genuinely believes it matters. "My generation and younger are the future of robotics, so it is essential we understand and take interest in this field," he says. "Building a robot hand with your own hands is a great way to learn about robotics."
There's something powerful in that statement. He's not saying robotics is cool to watch — he's saying it's cool to build. To fail, adjust, try again. To hold a working prototype in your hands and know you made it.
The LEGO hand won't replace 3D-printed versions in research labs. But it might end up in classrooms, maker spaces, and bedrooms across the world. And that's where the real innovation happens.
