Justin Lange


a device that allows a person with limited left-hand dexterity to play the acoustic guitar.

Introduction to Physical Computing

I grew up with my Dad's songs. Some of my first memories are of him and my Mom singing to me and my siblings. A bad fall last winter left my Dad with a dislocated shoulder and detached nerves. His function in his left arm remains very limited. And he sure can't play guitar.

I thought,'how about I just build something to allow him to get back to his songs?' Something of a Luddite at heart, he was a little slow warming up to the idea of an electronic device interfacing between him and an acoustic instrument. Furthermore, he was understandably a bit pessimistic; he said, "Justin, that sounds like a great idea if you've got a ten-million dollar research budget behind you, but I just don't think what you're talking about is possible". I said, "let me see what I can do".

My design revolves around three rows of solenoids, positioned just above the fret board at the base of the neck on the first, second and third frets. A series of buttons near the body allow simple, intuitive control over chord selection.

Pressing and holding the first button plays an "A major" chord; pressing and holding the second button plays a "B major" chord, and so on. Other buttons, for instance, "7th" or \"minor", modify the chords that the root buttons create; pushing "minor" and then "B" plays a "B" minor chord.

FolkBox is a prototype in early development. At the time of this writing, John, who lives in upstate New York, has not yet tested the device. We're excited and hopeful.

John is experiencing some nerve regrowth, at the rate of about 1mm every few weeks. It's not known how long this will continue, and even if it does, his range of motion will likely remain limited.

As John warmed to the idea of utilizing an assistive device, I investigated what kind of input might feel most "natural" to him, most akin to playing the guitar. We considered using a combination of buttons on the guitar and a foot pedal, but settled on using buttons solely on the guitar because it most closely resembled the form factor of the instrument. Because of his limited dexterity, the "modfier" buttons are toggle switches; he need only press a minor button to enter the minor "mode", wherein all chords will be minor until the mode is changed. This way, he doesn't need to hold down multiple buttons at once, a task that we anticipated might prove difficult for him.

Our conversations first revolved around (1) what it might feel like to use a mechanical/digtal interface, and soon moved to hands-on conversations, where he would hold a guitar and we would examine where his hand could comfortably sit. The idea of having the buttons anywhere near the frets that would actually be pressed was quickly scraped -- not only did he have difficulty moving his fingers, I learned, but he also couldn't move his arm up the fretboard. Thus, we chose the intersection of the body and neck of the guitar as the ideal location for the buttons. I quickly fabricated a piece of wood and taped it to the guitar to see if he could reach it.

Because the "folkBox" is controlled by a micro-controller, the input mechanism (the series of buttons placed below the fretboard) can be considered modular; it's not hard to conceive of other forms of input that could be utilized to put the device in the service of other disabilities. A full amputee, for example, could utilize the foot pedal input module that John rejected.