Jason Barnes, a drummer who lost one arm below the elbow in an electrical incident, built his own prosthetic device shortly after the accident.
"It wasn’t very flexible. He could bang the drums by moving his elbow up and down, but couldn’t control the speed or bounce of the stick without a wrist or fingers," said Georgia Tech.
Which is where Professor Gil Weinberg of the Tech's Center for Music Technology stepped in, creating a motorised single-stick device with EMG (electromyograph) sensors to respond to Barnes’ bicep muscles.
“I can flex and send signals to a computer that tightens or loosens the stick and controls the rebound,” said Barnes.
Weinberg speciality is autonomous music robots - having built a robot percussionist and a marimba robot that use algorithms to improvise with human musicians.
“The second drumstick has a mind of its own. It’s interesting to see the drummer playing and improvising with part of his arm that he doesn’t totally control,” said Weinberg, “Jason can pull the robotic stick away from the drum when he wants to be fully in control, or he can allow it to play on its own.”
Timing is everything in music, and learning from this project could improve assistance robots.
“Music is very time sensitive. You can hear the difference between two strokes, even if they are a few milliseconds apart,” said Weinberg. “If we are able to use machine learning from Jason’s muscles to determine when he intends to drum and have the stick hit at that moment, both arms can be synchronised.”
According to Weinberg, such robotic synchronisation could be used by two-armed humans to control a mechanical third arm to, for example, "help astronauts or surgeons perform complex, physical tasks in synchronisation with robotic devices". Brain activity might be a source of control signals as well as EMG, he added.
Barnes will play with the device publically for the first time tomorrow as part of the Atlanta Science Festival (Robotic Musicianship Demonstration and Concert, Bailey Performance Center, Kennesaw State University.