The HACKberry myoelectric prosthetic arm created by exiii Inc (a Japanese robotics company based in Tokyo that specializes in bionic arms) is taking the world of open hardware by storm with their latest 3D printable prototype.

The newly released open source prosthesis uses smartphone technology to process user data, replacing an expensive and often difficult to upgrade onboard proprietary computer system.

You can download the project documentation here.

The core team consists of Software Engineer, Genta Kondo; Mechanical Engineer, Hiroshi Yamaura and Industrial Designer, Tetsuya Konishi.









The teams sci-fi inspired bionic arm has been compared with Big Boss’s prosthetic hand from Hideo Kojima’s upcoming game, Metal Gear Solid V: The Phantom Pain. Other comparisons have included “Automail” the automotive armored prosthesis used in the fictional Fullmetal Alchemist universe and augmented technology from Deus Ex, a popular cyberpunk-themed action role-playing game.

“We think it is most important to optimize functions, save the costs, and give the hand a stylish design.”

The hand works by detecting when nerve and muscle tissue is stimulated by signals from the brain and sends that data to the user’s smartphone to translate into hand and arm movements. The system enables users of the prosthesis to open and close the hand and even control individual fingers.

“We will release all data of HACKberry as open source to develop this prototype alongside developers from all over the world…”

Users who wish to test the prototype can do so by downloading the released data and create it themselves. exiii are also partnering with Wevolver to enable anyone to join in the development of the project and easily build their own HACKberry with the support of the Wevolver platform and community.

By incorporating mobile technology that has already seen widespread adoption by the general public, exiii have arguably made the HACKberry the most advanced, affordable and accessible electronic prosthesis currently available.

The decision to incorporate smartphones to carry out the processing also means the HACKberry’s computational power will improve alongside advancements in consumer mobile technology, so when you upgrade your mobile, you will also be upgrading your bionic arm.

The engineering behind this prosthesis is as unique as its design; featuring an underactuated mechanism to control precise movements and obtain self-adaptability when grasping different objects with its 3DOF fingers, each controlled by a single motor. In comparison, almost all other available prosthetic hands are incapable of adapting to the shape of different objects in this way and rely on a simple hooking and clamping mechanism.









“Users can arrange color, texture and functions based on their preference.”

As well as saving money by outsourcing the data processing to smartphones, by producing the HACKberry using 3D printing means broken parts can be easily replaced, and the opportunity to customize with various colors, materials and finger combinations is almost limitless. Theoretically, you could print the HACKberry in aluminum or even wood. 3D printing is not limited to just PLA or ABS plastic.









“Our goal is to develop an artificial arm that would become the platform upon which developers and artificial arm users from all over the world can build as they wish.”

The exiii philosophy is just as interesting as the prosthesis itself and is clearly reflected in the name of the project.

“The name represents our vision to “hack” at problems, grow branches of joy that reach out to users and enable their ideas and efforts to bear fruit (“berries”).”

The HACKberry software (Arduino sketch) is available under a CC0 1.0 Universal, and the hardware (3D data, etc.) is available under a Creative Commons License BY-SA 4.0 International.

We will be assembling our own HACKberry at the Wevolver open workshop at Somerset House, where a core team and group of volunteers also be working on the InMoov Robots For Good Project.

You can contribute to the project and build your own HACKberry here.

Sharing open source technology makes collaboration possible and gives anyone access to the knowledge they need to take their ideas further.

Interested in starting a project?

Email me: cameron@wevolver.com

You can also check out projects I’m working on here.

Cameron Norris

Wevolver Community Connector