Teen Creates Advanced Robotic Hand Using Just Lego Parts

A robotic hand constructed by a 16-year-old boy and his father using Lego pieces can effectively grasp and manipulate objects, showcasing functionality akin to natural human hands.

Jared Leppola, a student at Bristol Grammar School in England, began working on this project with his father when he was just 14 years old. Nathan Leppola is affiliated with the University of Bristol.

The device utilizes concepts from leading research institutions like Pisa/IIT SoftHand, yet it is built entirely from readily available components from Lego Mindstorms, a popular series of educational kits designed for creating programmable robots.

“My father is a professor of robotics at the University of Bristol, and I was really inspired by the design of robotic hands,” Jared explains. “This motivated me to pursue it in an educational context using Lego.”

The hand operates using two motors based on tendon mechanics, and each of its four fingers is equipped with three joints. A differential mechanism made of Lego clutch gears connects the fingers, allowing them to move in unison until they contact an object and stop, mimicking human grasping behavior.

Throughout testing, the Lego hand successfully grabbed nine common household items, including plastic cups, bowls, and a stuffed toy weighing 0.8 kilograms.

When one finger is engaged, it fully closes in approximately 0.84 seconds and reopens in about 0.97 seconds. This speed is about half that of the Pisa/IIT SoftHand’s 3D-printed counterpart, which employs metal bearings. In static tests, the Lego hand could withstand loads of 5 Newtons, exert a pushing force of 6 Newtons, and deliver a closing force of 1.8 Newtons. Comparatively, the 3D-printed version can manage loads up to 8 Newtons, push with 7 Newtons, and has a closing force of 2 Newtons.

“You won’t find a better hand,” Nathan states regarding the 3D-printed alternative. “In terms of functionality, the LEGO hands are also considerably larger, with each finger measuring 145 millimeters long and 30 millimeters wide.”

While Lego Mindstorms was discontinued in 2022, Jared noted that the device can still be easily modified with a variety of Lego creations. “The way I designed the motor, you can simply take it out and replace it with a new one,” he explains.