THE CYBORG DRUMMER

Now, with the help of a custom bionic arm, Barnes is working his way through music college in America, while the engineer who designed his unique prosthetic describes his musical ability as literally “superhuman”.

Developed by Gil Weinberg from the Georgia Institute of Technology, Barnes’ prosthetic arm uses a mechanism called electromyography to pick up on the tiny electrical signals emitted by the muscles in Barnes’ upper arm.

When Barnes squeezes his upper bicep a motor in the arm adjusts how quickly it moves and how loosely it holds the stick. A second stick attached to the prosthetic beats entirely independently of Barnes, using built-in sensors to detect his drumming and then create its own complementary rhythm. That algorithm that Weinberg developed to create this responsive beat is apparently modelled on the rhythms of jazz greats such as John Coltrane and Thelonius monk. Weinberg has built a number of other musical machines, including a marimba playing bot that Stephen Colbert said combined “two of the biggest threats to our nation — jazz and robots.” Speaking to New Scientist about his new bionic arm, Barnes said the device was “pretty awesome”. “If it works out and it proves to be a lot more useful than my current prosthesis, I would definitely use it all the time,” he said.

Barnes, who lost half of his arm after being electrocuted cleaning a vent hood at a restaurant in January 2012, originally made his own prosthetic using a simple brace and a spring. It was rudimentary but it allowed him to enter the Atlantic Institute of Music and Media in Georgia.

At the institute, Barnes caught the eye of drum instructor Eric Sanders, who introduced him to Gil Weinberg at the Georgia Institute of Technology. The group hatched a plan to build Barnes a robotic arm that would allow him to play just as well as any human drummer — or perhaps even better. In the past, Weinberg’s lab has built a number of stand-alone musical robots, like robotic drummer HaileMovie Camera and marimba-playing Shimon. Both can listen to what human musicians are playing and improvise accompanying beats of their own.

“In some cases, we were able to create some surprises, with music that cannot be created by humans alone,” says Weinberg. “The next interesting step is to see what happens when you are part of the robot and the robot is part of you.”

For Barnes, the device needed to be able to take cues from the human body. The lab designed a pros- thesis that uses a technique called electromyography to pick up on electrical signals in the upper arm muscles. By tensing his biceps, Barnes controls a small motor that changes how tightly the prosthetic arm grips the drumstick and how quickly it moves, vital skills for a drummer. The researchers then added another layer of complexity — a second, autonomous drumstick on the robot arm. This second stick, controlled via its own motor, uses a microphone and an accelerometer to sense the rhythm Barnes is playing, as well as music from any nearby musicians. An algorithm then produces a new beat with a complementary rhythm and melody, modelled on the music of jazz greats like John Coltrane and Thelonious Monk.

With this extra artificial intelligence, human and machine combine to make Barnes a kind of “super- human drummer”, Weinberg says. It’s a common theme that runs through most of Weinberg’s work — the idea that robots can help us make music that wouldn’t be possible by humans alone. For example, software can crunch data much more quickly, he says. It can also combine different musical styles in unexpected ways.

“This could change the way we interact with our instruments in the future,” says Jack Baker, drummer with the band Bonobo. “It’s not only a great step forward for amputees but for drummers who are willing to use technology. I would love to see it in action.”

Sanders says he could definitely imagine playing with a robot in the future. “I have a fusion trio group that plays really challenging music. It would be kind of perfect to improvise with a robot and see where that takes us,” he says.

Since percussion requires such exact timing, Weinberg’s team hopes that its algorithms will find a home in other fields that require a high level of accuracy, such as self-driving cars or assistant robotic arms for astronauts.

The prosthesis will make its debut in a concert at the Atlanta Science Festival on 22 March. Barnes will drum alongside Sanders and some of the lab’s other creations, including a dancing robot named Shimi.