How do bionic limbs recgonize nerve signaling?

[Elite Engineer]

gif of girl with amputated hands using bionic hand: https://gfycat.com/VacantRequiredAmethystinepython

 

How does the bionic hand know/recognize nerve signals being sent to the area that would be her hand? Also, how is it calibrated that it provides the right amount

 

of tension with the nerve signal?

 

~EE

[Bender]

There are several ways:

- some people are born with something finger-like at the end of a stump, with which they can control a kind of switch.

- myo-electrical sensors can pick up muscle activity: in case a part of the lower arm is still present, so are parts of the muscles. These muscles can still be activated by the brain, and in doing so electrical signals are sent to the muscles, which can be detected. The nice thing is, to open and close the prosthetic arm, the same muscles can be used as for opening and closing a normal arm (this is most likely the case for this girl)

- implants can detect nerve activity. This can not only give control over a more complex prosthesis, it can even feed back information from tactile sensors in the robotic fingers.