Georgia Tech researchers have built a robotic arm that attaches to a drummer’s shoulder and plays along. This allows drummers — now equipped with three arms — to play sequences that two-armed humans can’t even attempt.

“It’s a richer and more sophisticated rhythm because you can hit one more thing,” said Gil Weinberg, director of the Center for Music Technology at Georgia Tech. The robotic arm is capable of hitting a drum up to 20 times per second, a rate that’s impossible for humans. And it never needs a break.

The computerized arm listens to the sound of the human playing and improvises to accompany the beat. Currently it can’t be programmed to play specific songs. The robotic arm will generally mirror the volume and speed that the human is playing.

Weinberg stopped short of saying the three-armed solution is presently better than what a drummer can do with two hands. The arm, finalized last week, hasn’t been tested yet to see how it complements professional drummers.

Weinberg’s next step is having drummers wear a brain-scanning headband, and see whether the robotic arm can interpret their intentions and play exactly what they desire.

Since 2006, he has worked to create memorable music through artificial intelligence. In one project, Weinberg built a robotic prosthesis for a drummer who lost an arm in an accident.

In the long term, he could see the technology being useful for doctors or technicians needing a third arm to assist them in their work.