Myo armbands used to control prosthetic arm

The Myo gesture-controlled armband has been used to create a robotic prosthetic arm that can be controlled by the user's muscles.

Johnny Matheny picks up a ball using the Myo-controlled arm.

Thalmic Labs/Screenshot by Michelle Starr/CNET

The Myo gesture-controlled armband has already moved beyond augmented reality, DJing and gaming, into the hospital surgery. Now it's show its potential for amputees, too. A team of researchers at Johns Hopkins University has used two Myo armbands as the interface to control a robotic prosthetic arm.

Amputee Johnny Matheny lost his arm to cancer in 2008. At the Johns Hopkins Applied Physics Laboratory, Matheny was fitted with a prosthetic connected directly to the bone in his upper arm. The Johns Hopkins team then designed a robotic arm that can be controlled using Myo.

There are several means of controlling robotic prosthetics, but they broadly fall into two main categories: invasive and non-invasive. Invasive interfaces are generally connected directly to the patient's nerves. Non-invasive interfaces are placed on the skin, using the electricity running through muscles as the patient moves them to control the limb.

This is called electromyography, and it is how the Myo armband works. The user makes slight adjustments to the position of their arm, which can be calibrated and interpreted into commands for the armband. It was only a short leap from there to prosthetics. Rather than design their own interface, the Johns Hopkins team tapped into Myo for Matheny's arm.

"The APL arm is the most unique arm I've ever worn," Matheny said in a video. "It has the ability to do anything that your natural hand, wrist, elbow, shoulder can do."

Matheny is able to use his fingers to pick up and manipulate objects. As he gains more practice with the arm, his control will improve.

However, it's not a perfect system. The Myo armbands pick up the EMG signals from his muscles, but they can't communicate directly with the robotic arm. The signals have to be sent wirelessly to a nearby computer to be translated into commands for the arm, and relayed back in real-time.

This means that, in order to be able to use the arm, Matheny needs to be within communication distance of the computer.

The project does, on the other hand, demonstrate the feasibility of an out-of-the-box product being used as a potentially lower-cost alternative to other mind-controlled prosthetic solutions.

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