The Brain Driver consists of a headset with 16 sensors monitor electrical signals from the brain. Clinical devices usually use 32 sensors, but Llarena and his team are trying to build something that’s as small, cheap and unobtrusive as possible. “We think that 16 are probably too many,” he says. “We’re trying to figure out if we can take half of them out.” But there’s only so much streamlining they can do before the signals get too weak. They’re already working with tiny, microvolt signals from inside the brain and trying to read and interpret them. “It’s as if we were putting a small microphone on one side and trying to hear one of a million people shouting on the other side,” says Llarena. After reading these signals through the skull, the system has to turn them into instructions for the wheelchair or car. The idea is that the driver thinks one distinct thought to turn right, and another left, while the electrodes pick up the associated activity. But those thoughts won’t necessarily be as simple as the words “left”and “right”; it could be something more abstract, like a certain place or a shape. “It was a long process because I didn’t know what to do at all. I was thinking of everything, the beach, red cubes, red circles.” Eventually he figured out that if he pictured a red cube in his mind, and then imagined that cube moving forward in his skull he could make the machine move forward. If he thought about that cube moving left, he could go left. Later on, the team realised that what he was really doing was activating his motor cortex, a process that sent out a strong enough signal to detect.
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