Prosthetic Hand That You Can Control With Your Mind

It’s hard to underestimate the complexity involved in any activity as simple as grabbing a pencil. This basic activity alone requires the coordination of hundreds of thousands of neurons to receive and fire their own signals, each at a specific times and certain points in space, stimulating specific muscle cells. It seems like a miracle that we would ever be able to replicate these processes using man made devices, but the technology is almost here.

HPA high school student Ilan Naibryf is currently designing a prosthetic hand that can be controlled with the user’s own mind. The project is really a coalescence of several advanced technologies, including 3D printed components, EEG brainwave sensing hardware, and mobile single-board computers.

The final design will be controlled by an Emotiv Insight EEG headset. This system is designed to read brainwaves and translate them into computerized data. Naibryf plans to design a program that can turn the data acquired from the Emotiv into a command that can reach robotic components, such as the servos that can be used to control his prosthetic hand. These servos will receive their commands from an Adreno computer that can wirelessly pick up the EEG’s data through XBee radio signals, which operate similar to bluetooth signals.

The mechanical design of the prosthetic is relatively simple; the moving parts consist of five servos that can be found in an elementary school robotics kit. The simplicity of this design is very clever, utilizing simple servos to act like contracting muscles, and string attached to act as tendons. The strings are connected to the servos and run through the joints of the prosthetic, so when the servo rotates, the tendon and the finger in the hand curl as a real finger would. Each servo is assigned to one of the EEG’s five channels, allowing the user to control each finger individually.

The project is in its early stages, but Naibryf has already produced the components for his first prototype. These components were all created using a 3D printer, making them lightweight and cost efficient. That was vital to this project, Naibryf wanted to prove that a more prosthetic components could be produced and utilized for an affordable price so that it can actually help people. Current prosthetic technology can cost between twenty thousand to eighty thousand dollars for a device that can perform functions only as simple as grasping. On top of that, most technologies are made very heavy with excessive use metal parts and motors. This project at HPA aims to produce a functioning hand (excluding the EEG) for under a hundred dollars.

The project is largely a proof of concept, proving that the technology doesn’t need to remain forever inaccessible to those who need it. that While this project seeks to improve the efficiency of the current prosthetic production process, new ideas continue push the limits of what is possible in the field. Currently, some projects are designing an artificial skin to use on prosthetics that can utilize humidity and friction sensors to relay touch sensation to the user. While this is outside of the scope of Naibryf’s project, he still plans on implementing an artificial skin using silicone that can generate friction similar to a real hand.

A working prototype should be ready by end of the first semester. Right now, the components of the prosthetic are very box-like and large, and they will remain so in the first model. After the first model is working, Naibryf plans to redesign his components to more accurately reflect a nature hand. The only problem that he anticipates right now is determining how he is going to gauge the strength of a human hand, and how he is going to reflect that with his simple servo and string design.

Arguably the most interesting part of this research is that it is being conducted by a high school student. Most projects in this field are either funded by the government, a large company, or at least a university. However, Naibryf only has access to the resources that the school already has, and this presents a challenge of a necessity for craftiness in the design of every component of the project. This craftiness will surely help produce technology that is accessible to more people.

Photos by Aaron Schorn.