Robotic extra thumb: https://www.newscientist.com/article/2277955-this-robotic-extra-thumb-can-be-controlled-by-moving-your-toes/ https://www.newscientist.com/a

Robotic extra thumb: https://www.newscientist.com/article/2277955-this-robotic-extra-thumb-can-be-controlled-by-moving-your-toes/ https://www.newscientist.com/article/2277955-this-robotic-ex... But they use toes to control the thumb instead of BMI.