It seems like hardly a month goes by without news reaching us of advances in the field of bionic hands. Unfortunately, however, these high-tech prostheses can be very costly to purchase, with prices ranging into the tens of thousands of dollars. This puts them out of reach of a large number of people, such as a boy that General Electric engineer Lyman Connor met last year. Connor proceeded to design and build a low-cost bionic hand in his home workshop, which he now hopes to make available to amputees-on-a-budget .... plus he hopes to get one to the boy, if only he can locate him.

Lyman ordinarily writes software for turbines and power plants, although he is also an avid tinkerer.

His story began last October, when he was in a serious cycling accident in his hometown of Roanoke, Virginia. He rear-ended a car that suddenly stopped in front of him, resulting in his receiving injuries that included nine skull fractures; a broken hip, jaw, clavicle and several ribs; a punctured lung; plus the loss of his sense of taste and the sight in one eye.

When he was leaving the hospital after a week of recuperation, he met a boy in the elevator, who had obviously been crying. When Lyman tried to cheer him up by pointing out his own injuries, the boy replied that at least Connor had both hands, and held up a wrist stump where one of his hands should have been.

At the time, Connor didn't know how to respond. Other things that the boy said, however, suggested that his family couldn't afford to buy him a bionic hand. Upon returning to his home, Lyman decided to build one that they could afford.

He started by 3D-printing fingers, based on a design created by the open-source South African Robohand project. He also found out about wrist design and bionic hand circuitry from the Michigan Institute for Electronic Limb Development, while members of the TinyCircuits DIY community helped him develop an Arduino-based TinyDuino microprocessor for use in the hand. Additionally, a local machine shop built the required metal joints and other components.

The now almost-complete hand is powered by a pair of USB-rechargeable lithium-ion batteries running in parallel, and can be operated in one of three ways.

Simple opening and closing can be activated by a set of integrated force-sensing resistors, that respond to pressure applied by the user. A suite of another 25 pre-programmed gestures, however, can be activated via an accompanying smartphone app – the phone communicates with the hand by Bluetooth LE.

Given that users might not want to be constantly tapping on their phones, however, the third method involves the wearing of a myoelectric bracelet on the user's "good" arm. Controlling gestures made with that arm are transmitted by the bracelet to the phone (which could be in a pocket or bag), and then relayed from the phone to the bionic hand.

Lyman still has to create an artificial skin covering, and hopes to ultimately make the entire hand commercially available as a US$4,000 kit – it's cost him about $10,000 to develop. He's aiming for an October 3rd release date.

That said, he never did get the name of the boy he met in the Roanoke hospital elevator last October. If you think you might know who he is, you can drop Connor a line at Lyman.Connor1@gmail.com

"Initially I wanted to research these devices and understand what was driving up the cost," he told us. "In the genesis I wanted to help out this young man and in the end provide a product that can compete at a fraction of the price and be available world wide to those in need."

The hand can be seen in action, in the video below.

Source: GE Reports