DIY Prosthetics

  • Do It Yourself Prosthetics Studio

    Using the open source RoboHand prosthetic as a basis for design, students re-envisioned the device to provide functionality beyond the capabilities of a traditional digit-based prosthetic. Students worked with the eNable online community which produces low-cost prosthetics to children for whom a standard prosthetic is cost-prohibitive and impractical due to growth. Students also worked with a local peer in need of such a prosthetic and are currently in the process of organizing a design charette matching users and young designers.

    DIY Prosthetics

     

  • The Ratchet Hand is a DIY prosthetic. Based on the open source RoboHand, we used that structure and reinvented our own hand. The Ratchet Hand uses the ratchet mechanism so that the wheel can offer multiple utensil holders. The hand offers an amputee to use a pencil, paintbrush, sharpie, fork/spoon, and knife. This allows one to use multiple utensils for various purposes from eating to drawing.

  • The Snap-Together Robohand was 3D modeled and open sourced to give people a cheap and easy way to obtain a prosthetic. Normal prosthetics can cost in the tens of thoasands of dollars. Although the original Robohand can close its fingers, it doesn't allow the user to do much else besides picking larger objects up. That's why the DIY Prosthetic  In the DIY Prosthetic studio, we were given the Snap-Together Robohand as a model and were told to modify it into a hand with a specific use. The Baseball Prosthetic uses a claw like closing motion which is needed to shut the glove. Moving the wrist up and down will open and close the glove.

  • Idea: Throughout 5 weeks Henry and I have worked rigorously on modifying the Snap-Together Robohand, designed to be a cheap 3D printable prosthetic for children. Our idea originated from our love of baseball. While understanding the limitations these children had, we came up with a design to open and close a baseball glove with the movement of your wrist.

    Design: We used a 3D modeling software called Rhinoceros to redesign all the pieces we needed to. Our first step was to look at all of the pieces of the hand. We realized that only half of it needed to change in order for it to make the motion we wanted. We started sketching out everything that needed to change and then designed the original pieces that we were going to change in rhino. After that was done, we started the modifying process. This included angleing and extending pieces, as well as creating completley new fingers that would be in different areas of the hand. After designing and printing all the new pieces, we ran into several problems and went back into Rhino to fix them. We had to create larger holes in the fingers for the elastic and wires to run through and we cleaned up some of our designs. Running into even more problems, Henry and I as well as another group met together and decided on a few key points in making our hands sleeker and more efficient. We went into another 3D software program called Inventor. This allowed us to join many of the pieces, cutting down on the total amount we had to print in half. Inventor gave us the ability to put all of our pieces together and see the movement that would happen when it was printed. Although we are still working out some details and issues that need some cleaning up, we have a prototype that looks leaps and bounds better than our very first. We intend on continuing our work on the Baseball Prosthetic after the end of NuVu. Our overall goal is to have our hand available on Thingiverse, a huge open source 3D printing community. This will allow anyone with acess to a 3D printer to make our hand and use it. We are very proud of the work we did for this project and hope that this inspires more people to get into prosthetics and 3D modeling.

     

  • The final model of the Swiss Army hand is a prosthetic for the physically impaired that is meant to help the user store and use tools. The hand comes equipped with a screwdriver and a wrench that are fixed onto a set of bars that are rotated by two wheels. The initial idea was to have a different tool for each finger however, we soon realized that in order for the extending and retracting mechanism to work correctly, the maximum number of tools was 2 tools. Once our group decided on which tools to use, we designed around them and figured out what other mechanics the hand had to have in order to work correctly. The inspiration for this came from a swiss army knife and from the superhero Wolverine. The multiple tool idea came from the concept of a swiss army knife, and the retractable tool feature was inspired by looking at the claws of the superhero Wolverine. The two tools are fixed onto two acrylic bars that attach to two rotating wheels. When the user bends their wrist, the fingers close and the two tools push out and extend past the fingers. When the user returns to the natural position the tools retract back in.

  • One of our task was to redesign the fingers. We liked the original finger shape more or less, but not the dimensions. We wanted the the thumb to have a different thickness than the other fingers so that it could pick up smaller objects.

    We had many struggles with this design because we wanted the fingers to do more precision work, but also wanted to give someone the ability to still toss a ball around with their friends.

    Our first problem that we ran into was interference. We did not give enough leeway to the fingers to connect to the knuckles. We also had another problem with the fingers because the connector pieces and the actual fingers holes that the pin would go through did not line up.

    Because we wanted two different sized fingers, we had to create a whole other finger from scratch. We had a big problem with the measurements. We wanted to have precision movements, so the thumb and the index finger had to touch, which they didn’t. We had to extend the platform in which the thumb was on a certain distance so that they would touch.

    I learned to always model around pieces as to not mess up any measurements and to think methodically about which pieces to create first so that you did not have to work twice as hard to get the next piece done.

    We had also found another problem with the original design of the RoboHand. We did not like how on all of struts there were two, and you had to put like ten pins on each side just to have that piece be pretty flimsy. So Nathaniel and I thought, why not just make it all one piece. The problem in our design for the knuckles though was that the knuckles were slanted, so when we printed the first prototype of the struts, it did not align right. We had to go back into Rhino and go and edit the struts to make one of the pieces longer.

    Another problem we had was the connector piece to the knuckles. This piece was not hard, but I just was not thinking when made it. I made this piece after the finger, which was the wrong choice, because the piece did not give the finger maximum angle to rotate. Also there was interference with the knuckles, and it gave it almost no angle to rotate. Eventually I made the right decision and modeled the connector piece around the knuckles and the fingers.

    The RoboHand seemed like a very rough design and was difficult to get working and adjusted the way we wanted it. Main problems that we found were that the original design was difficult to string up and adjust, it could really only grab larger objects, and it was a bit rickety. To solve these problems, we basically re-designed the entire hand.

    Starting off with stringing it up, we did away with having to tie knots on the body of the hand. It was basically impossible to string up each finger perfectly. Some of them might have less range of motion, and others would bend all the way. Instead, we took ideas from the Violin. In order to tune a violin, you take out a rod, twist it to your desired setting, and ram it back in. It stays in the hole because the tunnel is tapered as well as the rod. We implemented this idea into our hand and now it is much easier to string it up and make fine adjustments to the fingers. It also looks extremely cool.

    The knuckles also got a make-over. The original RoboHand had a straight knuckle and didn't allow for a wide array of movement. By angling it, much like a human hand, we could have a wider range of movement and possibly more grip. Unfortunately, this meant that we would have to change the side bars so the entire hand could rotate and still have parallel side bars. We also changed the position of the thumb to under the index finger which would make it more like a claw. This would make it easier to grab small objects. At first, we made a lot of mistakes. Our 3D models weren't closed polysurfaces, which became a huge waste of time and was extremely frustrating. But after making sure all of our objects were correct, we were finally able to print.

    Sadly, after printing out all of our pieces, and finally getting the chance to put it all together, we realized how many mistakes we really made. The pieces all had too tight of tolerances and would either not fit together, or have a lot of friction and not move freely. The only thing that really worked was our solution to stringing it up. It, for the most part, worked perfectly and would be a great design change for all of the other groups’ hands.

     

  • The Claw Hand, overall, was basically an improved design over the original RoboHand. We wanted to create a hand that had a higher range of movement, was able to pick up smaller objects, and something that could be strung up way easier than the original. By improving on each of these design flaws, we were able to create a more efficient and appealing prosthetic. In the end, the knuckles were curved to allow for a wider ranger of movement and so that it could pick up big objects with more grip. This was an improvement over the original RoboHand since the original had a very lateral movement. Next, we moved the thumb to the underside of them hand, underneath the index finger. This change made it more claw like and would allow the used to pick up smaller objects that wouldn't be possible with the RoboHand. Finally, we made stringing up the hand infinitely times easier. Using the violin string concepts, which meant that you could tune a violin by pulling out a tapered rod and twisting it, we were able to have a more efficient and adjustable string system. We believe that, with some more tweaks and looser tolerances, we created a much more improved, efficient, and functional design over the original RoboHand.

  • One of my task was to redesign the fingers. Nathaniel and I liked the original finger shape more or less, but not the actual dimensions. We wanted the the thumb to have a different thickness than the other fingers so that it could pick up smaller objects. 

    We had many struggles with this design because we wanted the fingers to do more presicion work, but also wanted to give someone the ability to still toss a ball around with their friends. 

    Our first problem was that I did not design the finger around the other part that connects to the knuckle, so when I tried to put the finger and the other part together in a rhino model the hole that were supposed to line up to put the pin through did not line up. I basically had to redesign the finger several times to get it just right, because either the holes were too small to put the string through or many other basic careless interference mistakes.

    Because we wanted two different sized fingers, we also had to create a whole other finger from scratch. We  wanted the thumb and the index finger to touch when you clamped we had to measure how long the index finger should be to be able to touch the tip of the thumb.

    I learned to always model around pieces as to not mess up any measurments and to think methodically about which pieces to create first so that you did not have to work twice as hard to get the next pice done.

    We had also found another problem with the original design of the RoboHand. We did not like how on all of struts there were two, and you had to put like ten pins on each side just to have that piece be pretty flimsy. So Nathaniel and I thought, why not just make it all one piece. The problem in our design for the knuckles though was that the knuckles were slanted, so when we printed the first prototype of the struts, it did not align right. We had to go back into Rhino and go and edit the struts to make one of the pieces longer. 

    Another problem we had was the connector piece to the knuckles. This piece was not hard, but I just was not thinking when made it. I made this piece after the finger, which was the wrong choice, because the piece did not give the finger maximum angle to rotate. Also there was interference with the knuckles, and it gave it almost no angle to rotate. Eventually I made the right decision and modeled the connector piece around the knuckles and the fingers.

  • After examining and building the original RoboHand, Sam and I took notes of what needed significant improvements. The RoboHand seemed like a very rough design and was difficult to get working and adjusted the way we wanted it. Main problems that we found were that the original design was difficult to string up and adjust, it could really only grab larger objects, and it was a bit rickety. To solve these problems, we basically re-designed the entire hand.

    Starting off with stringing it up, we did away with having to tie knots on the body of the hand. It was basically impossible to string up each finger perfectly. Some of them might have less range of motion, and others would bend all the way. Instead, we took ideas from the Violin. In order to tune a violin, you take out a rod, twist it to your desired setting, and ram it back in. It stays in the hole because the tunnel is tapered as well as the rod. We implemented this idea into our hand and now it is much easier to string it up and make fine adjustments to the fingers. It also looks extremely cool.

    The knuckles also got a make over. The original RoboHand had a straight knuckle and didn't allow for a wide array of movement. By angling it, much like a human hand, we could have a wider range of movement and possible more grip. Unfortunately, this meant that we would have to change the side bars so the entire hand could rotate and still have parallel side bars. We also changed the position of the thumb to under the index finger which would make it more like a claw. This would make it easier to grab small objects. At first, we made a lot of mistakes. Our 3D models weren't closed polysurfaces, which became a huge waste of time and was extremely frustrating. But after making sure all of our objects were correct, we were finally able to print.

    Sadly, after printing out all of our pieces, and finally getting the change to put it all together, we realized how many mistakes we really made. The pieces all had too tight of tolerances and would either not fit together, or have a lot of friction and not move freely. The only thing that really worked was our solution to stringing it up. It, for the most part, worked perfectly and would be a great design change for all of the other groups "hands".

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  • Using the open source RoboHand prosthetic as a basis for design, students re-envisioned the device to provide functionality beyond the capabilities of a traditional digit-based prosthetic. Students worked with the eNable online community which produces low-cost prosthetics to children for whom a standard prosthetic is cost-prohibitive and impractical due to growth. Students also worked with a local peer in need of such a prosthetic and are currently in the process of organizing a design charette matching users and young designers.

 
  • Do It Yourself Prosthetics Studio

    Using the open source RoboHand prosthetic as a basis for design, students re-envisioned the device to provide functionality beyond the capabilities of a traditional digit-based prosthetic. Students worked with the eNable online community which produces low-cost prosthetics to children for whom a standard prosthetic is cost-prohibitive and impractical due to growth. Students also worked with a local peer in need of such a prosthetic and are currently in the process of organizing a design charette matching users and young designers.

    DIY Prosthetics

     

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