Ethan & the Robohand

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This is Ethan, an adorable 5-year-old boy in Missouri. He was born with amniotic band syndrome, which affected the development of his right hand. When Ethan asked his parents for a prosthetic device, they quickly learned that all the options were outside of their price range. They began looking for alternatives and found videos of “robohand”, an affordable open-source alternative to expensive prostheses that is 3D printed. This is how I came to know them.

I immediately jumped on board. I had been cultivating an interest in bionics and prosthetic devices since my sophomore year of college. I always thought that was something I would do “later in life.” I was intimidated by it. I saw this as a great opportunity to use the skills I had to jump right in.

I met the family at my favorite restaurant in Columbia, The Heidelberg, and listened to their hopes and needs. Ethan was the first person I met with amniotic band syndrome (ADAM), and I did not see any reason why the robohand would not work for him. I noticed at the time that he was not able to flex his hand much, but I thought this could be amplified if needed. ™The following picture was one of several taken so that I could get dimensions of his hand from the quarter shown.

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™A good friend of mine, Derek Provance, and I teamed up to construction the robohand. All of the CAD files and instructions were available online, per its open-source quality. However, our access to a 3D printer was limited. Both of our RepRaps, homebuilt 3D printers, needed maintenance, and we did not have the money to go through a service provider. I decided to make an impromptu visit to Derek in Kansas City the day after meeting Ethan to see if we could get our printers working. Derek was a member of a hacker space, a community of DIY makers and hobbyist, called Hammerspace. One work session until 3AM and a blown out tire later, our printers were at least operational.

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Through Hammerspace, which also had some 3D printers, and using Derek’s printer as best we could, we pieced together a robohand. Because we didn’t have many options when it came to printers, the quality wasn’t high. However, it functioned and we wanted to have Ethan start testing it as soon as he could. We still weren’t sure if he would be able to operate it. I had begun to think up ways to modify the robohand for Ethan, but we wanted to test it first. Three weeks had passed at this point.

We grabbed one of my sister’s friends to serve as photographer and made the trip to visit Ethan and his family. On the car ride down, my sister’s friend began asking questions about the design. After explaining how the hand worked, I started to think up of other mechanisms that could serve a similar function. The trip passed in no time. A note to all readers, if we can ever talk design, you will win my heart.

We finally arrived to the family’s house, and were graciously welcomed in. Ethan was in the other room playing the Wii, and ran into the front room when he heard us. Derek held the robohand behind his back, and presented it in a very grand manner. Everyone was very excited. We had finished the terminal device (hand portion) but still needed to construct the “wrist.” We wanted to do it there so we could build it around him. We set up shop on the dining room table and began working.

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™Excitement quickly turned to disappointment, as we saw that it wouldn’t quite work out. Ethan didn’t have enough hand to attach the device, let alone operate it. We modeled the robohand after his good hand, and it was just too big. If we made the hand any smaller, it wouldn’t be useful for grabbing. In addition to that, even if we were able to attach this sized hand we feared he wouldn’t have the motion to operate it. We took castings of his hand and arm in orthoplastic to build off later, as well as more pictures of him flexing. We went back to the drawing board.

While the car ride back won the award for “most silent,” I wasn’t disappointed. I was thinking. All I could see was the problem at hand. I dropped the other two off and went to The Heidelberg to get a reuben. While I was eating, I thought back to the car ride down, where I was talking about design modifications that could make the robohand better. I pulled a notebook out of my backpack and began sketching. Soon more parts of the previous design were being replaced, until there was nothing left of it. In front of me was a completely new concept for a 3D printed mechanical hand. That was one delicious reuben.

I returned to Derek and showed him the drawings. We both agreed that this was a much more promising route to take versus modifying the robohand, and were excited to create something new. We just needed a name for it.

Continued in Gauntlet Initiative
Photo Credits:
[1] Maura Madinger

[2] Alex Madinger

[3] Maddie Frank

[4] ibid

[5] Derek Provance

Written on 20140512.

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