Handie: An affordable, functional prosthetic hand, made in Japan with 3D printing


See the original article in Japanese

Before we go any further, please check out the movie above. What you’re looking at is one of the many prototype devices developed for the recent Gugen hardware contest held in Tokyo on December 7th. Its developers are a team of three (a software engineer, a mechanical engineer, and a designer) who came together for this contest and developed this device. Users can create a functioning prosthetic arm by connecting the device with a smartphone, sensors, and a 3D printer. Affectionately named ‘Handie’, the prosthetic arm won contest.

Gugen is an event focused on identifying business-oriented hardware prototypes, and provides reward to top talent. A member of its executive committee, Yasunori Okajima, says the number of entries reached almost 200 this year.

Before participants were mostly those who enjoy creating electronics as a hobby. But this time, however, I see many more participants creating things that are business-oriented.


‘Makers’ is more than just a buzzword

Chris Anderson is a genius at creating buzzwords. He finds the structure of latest trends, and expresses that trend with one powerful word to facilitate an entire movement. When he published the books The Long tail and Free, even though the concepts were not brand new, many businesses then followed those trends. His most recent work, Makers, is no exception. Here in Tokyo, 3D printers appeared in many places all of a sudden, and media too have begun paying attention to this trend. A Makers boom suddenly started, but it soon cooled off.

What we need is not just a temporary trend or buzzword, but more initiatives like Gugen that try to tap into the inherent potential of the concept.

Three components for hardware creation

There are three components typically associated with developing hardware or electronics:

  • Create molding: exterior design.
  • Create software: the fusion of online and built-in software
  • Create electronics: open-source hardware such as Arduino


Because we can easily see and touch exteriors, 3D printers quickly became a sort of symbol for Makers. And this process of creating something from scratch is definitely exciting.

Handie’s exterior can be created at a reasonable price thanks to 3D printers. With data and printers, Handie can be created anywhere. However, there are two other important factors involved in building Handie:

  • All the software is smartphone apps, which cuts down the cost.
  • Motors and sensors are not customized parts. By putting general parts together, the team could create this device much faster.

Of course, Handie is not the kind of device anyone can develop. The most amazing part is its mechanical design. While multiple motors are typically needed to move fingers, the team managed to do it with only one motor.

And while not everyone can develop this level of device, as long as the developer has the core idea and the experience, they can create advanced devices like Handie.


Potential for business

Why is this new way of creating hardware and electronics getting so much attention right now? One of the reasons is that it represent significant potential for business expansion. When it comes to creating something entirely, the important thing to keep in mind is this notion of expansion.

Handie could never have been built without smartphone software. Yet with only smartphone apps Handie cannot be built. This is what I mean when I talk about expansion. As a result of such ideas, the shift from two dimensions to three dimensions has now accelerated.

For those who are interested in what kind of hardware can be developed by individuals, we’d like to list some of the other entries in the Gugen contest 1.


Squama is a screen that lets users can control transparency. At the contest, the developer mentioned that the panel can make an office more open while it also protecting privacy. In addition, it has an energy-saving effect in heated rooms.

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Universal Earphones

This earphone automatically recognizes if it was put into your left of right ear, and then proceeds to play the right sounds.

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As mentioned above, it aims to provide reasonably priced prosthetic arms using just a 3D printer and smartphone apps. It’s only for the people who lost a hand or the finger, it could be used as “a third arm” for everyone in the future.

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Telemba is a video-chat Robot created by connecting android devices and other electronic parts with a Roomba (robotic vacuum cleaner). It was quite amazing to watch the team members participated in the awards ceremony through Telemba.

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PocoPoco is an intuitive and sophisticated music interface. Each part was carefully chosen to realize elegant movement of the interface. PocoPoco played a short performance at the event, drawing a significant the audience.

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  1. You can see the whole list of entries on their website.  ↩