A 16-year-old from the UK has constructed a four-fingered robotic hand entirely from Lego Mindstorms parts, capable of grasping objects with forces comparable to advanced 3D-printed models. Developed with his father's guidance, the device demonstrates innovative use of everyday educational tools in robotics. The project highlights accessible engineering for students.
Jared Lepora, a student at Bristol Grammar School in the UK, began developing the robotic hand at age 14 alongside his father, Nathan Lepora, a robotics professor at the University of Bristol. The hand draws inspiration from cutting-edge designs like the Pisa/IIT SoftHand but relies solely on off-the-shelf Lego Mindstorms components, an educational kit for building programmable robots discontinued in 2022.
"My dad’s a professor at Bristol University for robotics, and I really liked the designs [of robotic hands]," says Jared. "It just inspired me to do it in an educational format and out of Lego."
The device features four fingers, each with three joints, driven by two motors connected via tendons. A differential mechanism using Lego clutch gears allows the fingers to move synchronously until they contact an object, mimicking human grasping. In testing, the hand successfully gripped nine household items, such as a plastic cup, bowl, and a 0.8-kilogram soft toy.
Performance metrics show the Lego hand closing a single finger in 0.84 seconds and opening it in 0.97 seconds—about half the speed of a comparable 3D-printed version with metal bearings. In static tests, a Lego finger bore 5 newtons of load, pushed 6 newtons of weight, and exerted 1.8 newtons of closing force, versus 8 newtons, 7 newtons, and 2 newtons for the 3D-printed model. However, the Lego digits measure 145 millimeters long and 30 millimeters wide, making the hand larger overall.
"You’re never going to get a hand that’s as good [as a 3D-printed hand] in terms of its capabilities with a hand made out of Lego," acknowledges Nathan. Despite limitations, Jared notes the design's modularity: "The way that I implemented the motors, they can easily be taken off, and newer motors can be added," allowing updates with other Lego pieces.
The project is detailed in a paper with arXiv DOI: 10.48550/arXiv.2510.15638, underscoring how affordable materials can advance student-led robotics research.