This “Ninja Turtle” Myoelectric Prosthetic Hand Was Built by the User

We try to avoid political issues as much as possible around here, but there is no way to tell this story without talking about the inadequacies of American healthcare. No matter how you think healthcare should work, there is no denying that we spend more on healthcare in the US than any other developed nation does. Most Americans are also almost entirely at the mercy of their health insurance providers — if they’re able to afford health insurance at all. Ian Davis had health insurance, but his provider refused to cover the cost of a prosthetic when doctors were forced to amputate four of the fingers on his left hand. Davis had to design and build his own prosthetic devices, including this “ninja turtle” myoelectric robotic prosthetic hand.

Davis’ bones were already weakened by a form of a cancer called Multiple Myeloma when he suffered a shop accident that broke many bones in his left hand and fingers. His doctors determined that four fingers would have to be amputated. His insurance company, in order to pay out as little as possible, made the ridiculous proclamation that those four fingers weren’t “medically necessary” and that Davis didn’t need a prosthetic. With his insurance company choosing to prioritize their bottom line over their client’s wellbeing, Davis, a mechanical engineer by trade, had to resort to developing and constructing his own prosthetic devices. He has created several of them with varying capabilities, including the amazing Terminator-esque mechanical hand that we featured a few months ago. In his newest video, Davis shows off a “ninja turtle” prosthetic that he created in the past.

This particular prosthetic hand got its nickname because it has two chunky fingers. When combined with Davis’ biological thumb, it looks a lot like the three-fingered hand of a Teenage Mutant Ninja Turtle. As with many of Davis’ other prosthetics, this one features myoelectric control. That means that it is capable of sensing electrical signals that are sent to Davis’ muscles and uses those signals to trigger the movement of the finger servo motors. This particular device is controlled by an Adafruit Metro Mini development board, and has a small OLED screen and thumb-operated buttons for adjusting the movement parameters. Davis can, for example, press flip between three movement speed settings to accommodate different scenarios.

This isn’t the prosthetic that Davis uses on a day-to-day basis, but it is still very interesting to see in action. Of course, it wouldn’t have been necessary at all if Davis’ insurance company was ethical and provided a prosthetic. Unfortunately, not many amputees possess the engineering skill to build their own prosthetics.