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Duke eNable

Enabling the Future at Duke University

Welcome to Our Blog!

Hi Everyone,

Thanks for checking out our Duke e-Nable Blog. We’ll use this to keep you up to date on all the cool projects we’re working on. Check back often for new posts!

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Featured post

Duke eNable starts its 2017-2018 season!

Hello all! Duke eNable has started our 2017-2018 season strong with a successful first interest meeting and general body meeting. We have split into several electrical teams and teams for our recipients Kaylyn and Nathan, and we have begun working on our first few projects. Looks like our members are excited for a productive year!

Getting to Know Brooke Reagan

Since we last introduced you to Brooke, she has graduated pharmacy school, accepted a full time pharmacy position in New Jersey, and has told us about how she became a pharmacist.

Hailing from North Carolina, Brooke has one sister who went to the University of North Carolina at Chapel Hill. Born with a congenital amputation, she came to Duke around the age of 5 and received a hook prosthetic arm, but she never got used to it. She tried to wear it for about a week, but in the end found that she was better off without it.

Brooke majored in history with a concentration in women’s studies, focusing on women in Africa and the Middle East. She went to graduate school with hopes of becoming a history professor, but while working part time as a cashier at a pharmacy during her second semester, she realized her true calling and switched into pharmacy. She went back to community college and completed the prerequisites for Pharmacy School, an arduous task.

Before she went off to Pharmacy school, Brooke tried her chances with an aesthetic prosthetic hand, but unfortunately the lack of functionality forced her to leave the hand in the glove compartment of her car for most days.

She enjoys leisurely traveling and recently got a Great Dane puppy named Turtle! She plans to move back to North Carolina in the future with her fiancee who is the director of a hospital.

We’re excited to meet with Brooke again and deliver her arm!

Haiti Trip 2

Our second trip to Milot was a resounding success. We spent about 4 full days there and were able to deliver a functioning arm to Chris and his family. We arrived in Haiti on Monday evening and attempted to get a good night’s sleep before we started our work with Chris (though the noise outside, the heat, and the crazy Malarone dreams made that a bit tricky!).

No time to loose

On the first day, our goal was to test the fit of the arm and make adjustments from there. The arm itself looked great on Chris; the positioning and length were correct and looked natural, which was a huge step forward from the first prototype. As the socket was loose in places, extra foam had to be added around the top rim and at the base to improve the fit. The straps and the harness were not sewn before the trip because we felt it best to sew the final product when the fabric could be positioned properly. We placed the harness and straps on Chris and pinned them where they were best fitting and most comfortable. Later in the day, everything was sewn together.

Hold on…

Compared to the first trip, the hand was adjusted to make gripping larger objects easier. This was accomplished by curving the thumb to hold round objects; our standard test was holding a plastic water bottle. The design was successful, though not without its faults. Chris was able to hold a bottle with the hand, but struggled with initially grabbing it and sometimes maintaining the grip. When he attempted to hold the bottle in the gripper thumb hand and unscrew the top with his other hand, the bottle would rotate because there was not enough nonslip material. We decided to make some adjustments to the hand and test again the next day.

{Non}slip and slide

The second day was spent implementing and testing adjustments from the first day’s observations. The harness was sewn together and the elastic straps were sewn onto the socket. Additional Dycem was added to the inner side of the thumb to increase the amount of nonslip material in contact with the object being held. After making these adjustments, we went to visit Chris again and tested everything out. The additional Dycem made it easier for him to maintain grip on the bottle while twisting the cap with his other hand. However, he still struggled with the motion of grabbing with the hand, because it requires the application of force at a specific angle. We spent the next bit of the day brainstorming a way to solve this problem, and ended up adding a small patch of Dycem to the upper part of the thumb. With this added material, the thumb was less likely to slip once it was positioned on an object. When we brought this idea back to Chris, it was noticeably easier for him to activate the gripper thumb hand and grab the water bottle. He and his family were happy with these adjustments, so we decided that this would be the final version of the arm!

Armed and ready

On our last full day, we assembled a second arm for Chris and compiled all the extra parts and tools that the family would need to maintain it. We delivered these things and explained to the family what the next steps would be, describing how to replace foam and Dycem, how to change out the socket for a wider one if needed, and how to make adjustments to the thumb. The most important thing we stressed is that Chris will need to practice with the arm to increase his strength and get more comfortable with how it works. He has the resources and information to make the most of what we have been able to give him, and the ball is in his court now!

Haiti Updates: August 13

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Bonswa tout moun! (Hello everyone) Our travelers made it back to the states late Friday night after a tiring but successful trip to Haiti. Be on the lookout for a longer post soon with stories and pictures from Milot!!

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Haiti Updates: August 7

Well, it’s time once again to pack up everything and head down to Haiti! It has been a little over a month since our last trip and we are ready to present Chris with his final device. We have packed many things including …

  • The complete arm
  • 3 spare sockets
  • 3 spare forearms
  • 1 spare gripper hand
  • Extra foam
  • Harnesses, straps, and extra material
  • A variety of tools including screwdrivers, calipers, and a protractor
  • A hairdryer
  • Paint and paintbrushes
  • 3D structure scanner
  • Camera and GoPro
  • Soccer ball
  • A partridge in a pear tree

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Emily and Joel will arrive in Milot this afternoon and depart on Friday. This week, the goal is to fit the new arm, test its efficacy in different scenarios, and make final adjustments. We will also begin to plan for the next steps in our work with Chris.

You have to hand it to these strapping young students that they have a firm grasp on what will enable their success. (I will not apologize for this sentence)

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Haiti Updates: August 1

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After a rather eventful month, we have finished the new arm for Chris! The updated version is printed in skin-toned filament and makes use of the modifications we have been working on since the first trip.

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On Monday, Emily and Joel will travel to Milot to meet with Chris again and test out the updated arm design. As the departure date approaches, we are working hard to print extra parts — some with larger dimensions — and acquire additional pieces of hardware and tools that could be useful during this trip.

Haiti Updates: July 25

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Many hands make light work

As we approach the deadline for the second trip to Haiti, things are really starting to come together. The socket and forearm are just about done and only need some minor adjustments. Besides the overall fit of the socket, two of the major problems that we wanted to fix were the length and angle the arm. The length needed to be decreased and the angle needed to be brought more towards the body. After some adjustments to the location of the screw holes, we are pretty confident that these problems are solved. Moreover, we decided to add an additional screw hole to both pieces so that we have two options for the angle, depending on how the screws are placed. The two pictures below show these options.

The most recent modification involved adapting the location of the screw holes in order to embed the screw heads beneath the inner surface of the socket. This design will enhance the integrity of the connection and make the bottom of the socket more comfortable by moving the hardware out of the way. Once this is finalized, we are ready to print the final arm and various extra pieces in skin-colored filament.

Get a grip

The final hand is also just about completed. In order to further increase the grip capabilities of the hand some sticky grip material was added on the inside of the thumb. This should prevent larger objects from slipping once grabbed. The material we will be using for the final arm has arrived as well, and as a test we printed the final hand design out with it.

Buckle up kids

This week we solidified the design for the detachable piece between the harness and socket.The black webbing in a V-shape provides integrity to the apparatus by combining a high strength, durable material with a configuration that adequately distributes the weight of the arm. The bottom two straps will be adjustable using simple rectangular buckles, and the top two straps will be sewn onto the harness once we fit it to Chris.

Lastly, we adapted the design for the straps on the socket itself. In order to provide a user-friendly and effective fastening system, we decided to affix elastic straps to one side of the socket, with Velcro patches on the bottom that attach to the other side. In this way, we can still use the elastic to provide a compressive force that helps stabilize the socket, while allowing Chris to adjust the fit with his other hand.

Haiti Updates: July 18

Since returning from Haiti, we have been working on the individual pieces of the device to make specific modifications. Once these are finalized, we will reassemble the device and prepare for the next trip!

Put a sock (in) it

The laser scan was imported into the CAD software to allow for a virtual fitting. With this, the original socket was edited in order to better fit the arm. Some adjustments still have to be made to the socket, as the fit was tight in a few places when the foam was added to the interior wall. All in all, things are coming along well, and a finalized socket should be done within the week. Ensuring the forearm will be angled naturally will be the harder portion of the design.

Need a hand?

For the most part, the hand did not need any adjustments. One thing that we did want to change, however, was the shape of the thumb. The first thumb design was mostly straight and would tend to slip on larger curved objects, such as water bottles. To fix this problem we decided to rotate and curve the thumb so that it will wrap around objects more. We also plan to add grip to the inside of the thumb to further prevent slipping.

Sew it goes

The overall design of the harness succeeded in transferring the weight of the device from Chris’s arm to his back and shoulders. The main change we want to make is to connect the socket by straps with buckles, so that Chris can put the harness and socket on separately. This way it will give him the flexibility of wearing the harness underneath his shirt if he wants. Another slight variation to this version involves adjusting the angle at which the straps cross in the back. Shoutout to Iris for being our model!

The new version has been sewn together, and the next step will be finalizing the design for the detachable connection to the socket. Below are some of the options.

Casting call

Last week we used the plaster cast, made from wrapping plaster gauze around Chris’s residual limb, to make a replica of his arm. A mixture of Plaster of Paris and water was poured into the mold and allowed to dry; then the gauze cast was cut away to unveil the final result. While the surface is still rough from the texture of the gauze, the shape is consistent with the 3D scan of the arm, which we scaled and printed out. We can now use both models to test the fit of the socket.

First Haiti Trip Success

Our first trip to Haiti was packed with challenges, uncertainties, and adventures. The hospitality and kindness we were met with was unparalleled, and it was exhilarating to get a glimpse of the potential impact of this arm.

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Armed, but not dangerous

Things the TSA has a problem with: flammables, Galaxy Note phones, liquids, aerosols, sharps, — and the most dangerous item of them all — plaster mold… which had to be checked three different times in three different airports. Somehow, various sized hands and sockets and forearms placed in a suitcase between clothes didn’t warrant a second scan — that dubious honor was given to the water bottle in Gabriel’s backpack. (He’s really not that good at packing — on the way back he left the bug spray in his bag, needing the Haitian TSA to search the bag and throw the spray unceremoniously into plastic trash can filled with things travellers shouldn’t have packed in the first place.)

A new angle

The various sized sockets and forearms came in quite handy (heh…).  The version of the socket based on the picture measurements was slightly too small. The upscaled version was better, but was still a little tight near the top and bottom of the socket. The bend between the socket and forearm ended up going away from Chris’s body, rather than towards it, which will necessitate changes in the design in the upcoming week. The straps for the socket have to be edited slightly to have them hold the arm better, especially near the end of the limb. The elbow of the prosthetic was in line with his elbow (whooo :D), though the forearm was too long (awww 😦 )

 

The harness succeeded in transferring some of the weight from the device to Chris’s back and shoulders. The main change we plan to make to the harness is making it detachable from the socket via buckle straps; this way the harness can be put on separately, underneath a shirt, and then connected to the socket. Similarly, we plan to change the the straps on the socket so that Chris can insert his limb into the socket from the side and close the straps around it, rather than sliding it in from the top.

It takes two to tango

And by tango we mean to use a laser scanner in order to take measurements. It’s a surprisingly intricate dance. One person holds the laser scanner, trying to keep the USB cable from getting too tangled or in the way of the infrared camera. The other person holds the laptop with the image from the camera visible to the person scanning, so that the one scanning can be sure the limb will is in view. And now begins the hard part, a crouched shuffle to the right and around Chris’s arm, which is raised up towards the ceiling while he lays on his side (surprisingly difficult when it comes to directions, especially with vire meaning “to turn” and rive meaning “to arrive” sounding so similar. In the end, Gabriel ended up laying down on the floor in demonstration, which resulted in a rare Chris smile that unfortunately was not captured on camera). We wonder what everyone else was thinking as we slowly moved around Chris, trying to avoid bumping into walls, chairs, or tripping over Chris’s legs while keeping the camera at the optimal distance for measurements. We didn’t have too much time to think about that though, focusing instead on making sure the scan was working, and feeling the the sweat slowly slide down our backs from the heat and the nervousness.

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A gentle tug-of-war

A plaster cast was used to make a mold of the arm, so that we could take back a physical version of Chris’s arm. We will later fill it with plaster so that we can use it to test the sockets we print. It was not without its challenges though. Getting the cast onto Chris was the easy part…. removing it proved much more difficult. Chris’s arm is slightly wider near the end, so trying to remove the cast proved fruitless. In the end, we cut open the mold from the top to about half way down one side, and then put the mold back together using excess plaster. While the mold will not be perfect, it will allow us to verify the sizing of the socket with an approximation, and will work especially near the end of the limb, which is the hardest part of the socket to model well.

Sometimes the old ways are best… (because it’s always a good time to quote Bond)

We took manual measurements of the arm using a tape measurer and — because no true engineering student is too far from it — a pair of callipers for that extra (and slightly unnecessary) four digits of precision after the decimal. The measurements will serve as a means of verifying the current design and will serve for scaling the result of the laser scan.

Be on the lookout for another blog post soon where we will share our personal impressions of Haiti and the trip as a whole!

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