E-Nable(ing) Shea To Build A Prosthetic Hand For Herself!


Here’s a heartwarming story for the day. Introducing [Shea], a little 9-year-old girl with a prosthetic hand made possible from a community of internet strangers!

She was born with only the palm of her right hand and a two-digit thumb — no fingers. Despite this day and age, prosthetics aren’t generally that good, or affordable — especially for a quickly growing young girl. So when [Shea] asked for a new hand from Santa before Christmas, her mom, [Ranee], started doing some research online. She had seen 3D printed prosthetics through Facebook posts and managed to track down the E-Nable group, which is a community of maker’s dedicated to lending a hand — quite literally.

The group got her in touch with [Nick Parker], a high school student and robotics enthusiast from California eager to help, who then introduced her (online) to his local Makerspace — from there they connected with the Milwaukee Makerspace (closer to home), and [Frankie Flood], an associate professor at the University of Wisconsin-Milwaukee.

[Flood] started work immediately, although he wasn’t quite ready for the three-day deadline little [Shea] had given just days before Christmas. He took a few of the designs already available online including the original Robohand, the Talon Hand, and the Cyborg Beast and started tinkering.


By creating parts for the hands in all of [Shea’s] favorite colors, he further refined the design, becoming more and more familiar with its function. In February, [Shea] and her family visited UWM to try out the first prototype. Within seconds of putting it on, [Shea] was already excitedly picking things up! The hand works by using wrist movement to open and close the hand — it’s relatively limited for now, but compared to not having fingers, it was an amazing new experience for [Shea].

As [Flood] puts it:

It made my year to see her pick something up with her new hand, it had to be one of the coolest feelings I’ve ever experienced.

They will continue working on refining and redesigning the hand with her, which will also be made available online for all, aptly called “Shea’s Hand”. Doesn’t this just make you want to get out there and help someone, like her?

More information about E-Nable and the project “Shea’s Hand” can be found on their blog.

34 thoughts on “E-Nable(ing) Shea To Build A Prosthetic Hand For Herself!

  1. “asked for a new hand from Santa before Christmas” – wow. Glad she got a better prosthetic.

    That’s got to be a big challenge to get the proper prosthetic for someone in this situation. Definitely not a one-size fits all solution.

    1. It is a big challenge… and a lot of the people designing things are using different software, so there’s the issue of converting file formats and what not, since things need to be tweaked/edited for each person. There’s at least one guy working on a parametric model in OpenSCAD which would be great because OpenSCAD is open source, therefore anyone could have access to it, and making it all parametric would allow people to get all the measurements (there’s a lot of measuring of the person’s limb/partial hand involved) and plugging the numbers into variables in OpenSCAD.

      For Shea’s hand (and many others) Frankie made molds and used that to work from, and even 3D scanned the mold to check for a good fit. (Also, some people have partial fingers, or a thumb, so edits need to be made for the files to accommodate that.

      There’s a ton more great posts on Frankie’s blog worth checking out, he covers the process (with photos) very well: http://frankieflood.blogspot.com/search/label/e-NABLE

    1. could they sure there are no real rules on this I believe. the real problem is getting the for profit compny they work for to let them when they make so much more money the other way.

  2. If you charge for it, the lawyers will come.
    Making and fitting prosthetic devices is a medical specialty that has it’s own set of liabilities. Nerve damage, ulcerations failures of the device. That said, to-date no one has been sued, and I’ve never heard of Santa or his helpers getting sued.

      1. Hypothetical situation here: someone is driving a car with a prosthetic hand, the hand malfunctions and the diver kills two pedestrians, the driver is also inebriated.The driver pleas not-guilty to charges of vehicular manslaughter because the device malfunctioned. Would it be unreasonable for the relatives of the deceased to also sue to the person who made/sold the prosthetic hand? Is the driver the only one who is guilty? What if the driver wasn’t drinking – then who is liable for the deaths?

        It becomes fairly obvious that the liability of manufacturing prosthetics can be a real barrier to casual entry int the industry.

        1. You just slap a warning label on it. Not a medical device. For amusement only. Do not use to operate heavy machinery. These statements have not been evaluated by the FDC, this product is not intended to treat or cure any disease. Etc.

  3. Shea is definitely a Jedi now. I have a feeling she will be a force for good in the future. Awesome story about people reaching out and solving problems. This is the world I want to live in.

  4. Here is the design I’d love to make for a prosthetic:


    Watch at 2:40 on..
    I can’t translate French well enough. I emailed the artist, but he didn’t respond. I find his automata beautiful and elegant. Would be nice if he made his prosthetic hand design open source, but also understand if he would like to preserve his intellectual property (and make money off it, if he so chooses). There are more videos of his stuff on the Tube..

    1. He said he found the design idea while eating crayfish, which has an animated external skeleton. And the hand is controlled by a single cable attached to a harness on his back : rounding your back pull the string, stick out your chest release the tension (or the other way around perhaps, it feels more logic like that).
      That give quite some clues to figure out how it works. The not so obvious thing is how is balanced the tension of a single rope between all fingers ? He said the tension is divided between fingers and you can see him grabbing an object with only 1 finger, the others just come to a rest on the palm.

      Hope it helps!

  5. Hold out your hand and look at the knuckles where the fingers join the palm. They aren’t in a straight line. On all these 3D printed prosthetics, they are. When you bend your fingers, the out of line knuckles arrange the fingers into a curve, forming a cup shape from the palm and fingers which helps grasp objects. The bones of the palm also have some movement back at the wrist so the palm can flex.

    Hold a hand in a neutral, relaxed position and observe how the knuckles naturally form a curve. Another thing I notice is these prosthetics mostly have fingers all the same length with joints in the same locations. What’s with the thumb sticking out at a 90 degree angle? Natural thumbs aren’t connected like that.

    Has anyone designing these actually *looked* at natural hands and observed how the variation of bone lengths and joint locations is responsible for the flexibility of the human hand which allows it to hold an immensely varied range of things?

    Study your own hands, get a set of replica human hand bones and observe their dimensions and how they fit and work together. Think of applying biomimicry to design a *hand* instead of a hinged paddle.

    If I had a 3D printer, that’s the design I’d work towards. (I have four NEMA 17 motors, a breakout board and some 40×40 mm t-slot extrusion and brackets.)

    For nearly 25 years I’ve had an idea for how to make “muscle” that would be compact, quick moving, strong and require no direct electric connection. No company involved with prosthetics or robotics will pay any attention to me because I don’t have an expensive piece of paper hanging on a wall as “proof” I have any clue about such technology.

    With that kind of attitude the world wouldn’t have light bulbs, electricity, airplanes, automobiles or even inexpensive cotton fabric. The major advances and inventions which made today’s technology possible came from many people who had at most a high school education – often combined with financial backers who were able to see the genius instead of just the “lack” of more schooling.

    Never forget people like Eli Whitney, Philo T. Farnsworth, Thomas Edison, Nikolai Tesla, Alexander Graham Bell, William Henry Perkin, Orville and Wilbur Wright (and all those who *nearly* made an airplane work), Charles Goodyear and all the tinkerers and inventors around the world who discovered and created amazing things.

      1. First thing is, they want to know revealing details about the concept *before* signing an NDA. Right, pull the other one. Tell ’em details, they say “Not interested.” then some time later they’re putting out a press release about something they “invented”. Happens to lots of people.

        So here’s my concept, throwing it out there open source, public domain, suck it greedy companies! ;-)

        Organic muscle fiber is made up of small cells, each of which only contracts a short distance. The combination of millions of short contractions in line adds up to the long movements of the entire fiber. Each of those cells as it contracts also gets wider. All the muscle fibers combined together in parallel, with all the cells shortening and widening, make the muscle bulge as it contracts.

        For many years there has been a method of a gross simulation of that action, a tube of elastic material, sealed at both ends, surrounded by a woven layer to constrain it and add strength. Pump air or liquid into the tube and the woven layer prevents the tube from stretching lengthwise yet allows it to expand radially. Since the length of the tube wall cannot change, the force pulls the ends towards each other. The shape changes much like the shape of a muscle.

        Now here’s my twist on it, involving some biomimicry. Instead of using a single, large tube as a stand-in for a muscle, and instead of a continuous woven layer, use a bundle of many small tubes, made of a material which resists lengthwise stretching. Mold many hard rings along the length of each of those small tubes. (Current technology should be able to extrude them with alternating hard and elastic materials.)

        The hard rings divide the tubes into sections which act like the individual muscle cells, each pulling a short distance but added end to end and in parallel should pull a long distance and with plenty of power.

        And there you have the information which some companies I contacted in years past tried to get out of me without signing an NDA. (It’s a series of tubes, but not Ted Stevens’ series of tubes.)

        One application I envisioned for the technology was the muscle at the base of the thumb, the one which pulls it in towards the palm. That seems to be a problem for even the most elaborate and expensive prosthetic hands. That motion of the thumb, with its range that allows the thumb tip to touch all the fingertips, is unique to the Human hand.

        No other primate hand has a thumb quite like ours. Many primate species cannot touch their thumb tip to all of their finger tips, some cannot touch their thumb to any of their finger tips.

        For a prosthetic replacing an arm instead of just a hand or part of a hand, this design could be used to duplicate the function of natural hand muscles, most of which are in the forearm. (Grasp one of your forearms with the opposite hand then wiggle your thumb and fingers. Feel and watch how the mechanics of hand motion operate.)

        I’ve seen a large scale arm like that, using the single tube “artificial muscles” but that design wouldn’t allow for building one human sized. Multiple small tubes that would be extruded in alternating hard and elastic materials could make it possible.

        Instead of complex servomotors and gears, only simple solenoid valves would be needed to allow air or fluid into the tubes then let it flow out. A fluid could be recirculated to a reservoir with a single pump. Air would require a tank or compressor. A tank would run out of pressure and an air compressor, no matter how small, would be louder and most likely use more power than a fluid pump.

        Every application requires different thinking about ways of applying a technology. For a small application of just a thumb base muscle, a small air reservoir periodically recharged with a hand pump might be workable while a replacement for an arm could have space for a rechargeable battery, fluid tank and pump.

        1. Pneumatic bladders have been proposed as muscles, both in robotics and prosthetics, altho it hasn’t taken off quite yet. They don’t work exactly the way you specify, tho some stuff I’ve seen is reminiscent.

          I think your problem is, disability isn’t big business. It’s a lot of small businesses, and of course every case is different as is mentioned here. For the industrial, robot, market, the problem is the huge amounts of R & D needed in anything, to adopt a new paradigm like this would cost squillions, and pistons are already available and well understood. You’d have to offer something really useful and profitable to get someone to do the necessary investment in bringing it to work. That, and the chance of failures so far not known about, I think would put people off.

          I think you’d need to find one area to be outstanding, world-beating in. Whether it’s power, space, reliability, or whatever. If your design is miles ahead better in some way, then it might take off. Even then it’d need good luck.

          Still doesn’t mean you’ve nothing to offer at the smaller end tho, exactly in things like this, small custom solutions to individual disability problems. Maybe suggest it to the people who already do it? Probably don’t expect a lot of money.

    1. Instead of copying a natural hand, it would be even better to design something that’s optimal for performing the desired functions based on the strengths and weaknesses of the technology that’s used.

      1. Since it’s copying a hand, that tells you what the desired functions are going to be. And nature’s spent a lot of time and material “designing” the one we already have. As well as that, the human world’s built for people with 2 hands to access and operate. That’s us all over, versatile, jacks of all trades. I couldn’t think of a better tool for all the jobs we do. Tho of course it’d be interesting if anyone’s thought of any alternatives.

  6. Great story. One item of caution for anyone wanting to build prosthetics…. (Unless things have changed since I was in the industry) you should be very careful about money changing hands after you build a prosthesis. There are obvious liability issues but one thing that isn’t so obvious could land you in court. Building and donating is one thing, but if you get paid–even if you are reimbursed for materials–you are at risk of falling under FDA regulations for selling a medical device.

      1. It is the type of situation that made me decide to work in the automotive industry after getting a degree focused on orthotics and prosthetics.

        Unfortunately, I’ve also heard of similar issues with making prosthetics for the poor in Brazil.

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