Researchers are one step closer to creating a prosthetic hand that allows user to have full control over each finger, according to a new report from Georgia Tech.

Researchers at the university say they have created an ultrasonic sensor which allows amputees to control individual fingers on a prosthetic hand, with enough sensitivity to play the piano, according to the report.

“Our prosthetic arm is powered by ultrasound signals. By using this new technology, the arm can detect which fingers an amputee wants to move, even if they don’t have fingers,” project lead and Georgia Tech College of Design professor Gil Weinberg said, according to a press release.

The prosthesis is an improvement over existing electromyogram-controlled prosthetics, which use sensors attached to arm muscles and can be activated to flex fingers and clamp with the user’s thumb, according to the report.

Instead of using a muscle sensor, the device uses an ultrasound probe which watches how the user’s arm muscles move, and sends signals on to a prosthetic hand to simulate digit movement.

“EMG sensors aren’t very accurate. They can detect a muscle movement, but the signal is too noisy to infer which finger the person wants to move,” Weinberg said.

The patient involved in the experiment, James Barnes, had his arm amputated just below the elbow after suffering an electrocution-related injury at work. While he lost his hand, Barnes maintained the muscles in his residual limb that would control his fingers, according to the report.

This allowed the team to monitor muscle movements in his arm, and track where movements differ when he’s trying to move different digits. Using machine learning, the system was able to detect continuous and simultaneous movements of each finger and monitor the force the patient intended to use, researchers reported.

“It’s completely mind-blowing. This new arm allows me to do whatever grip I want, on the fly, without changing modes or pressing a button. I never thought we’d be able to do this,” Barnes said, according to the release.