Designers: Eric Martin, Amy Peniston, Joshua Chao
Client Coordinators: Stephanie Parken, OTR
Supervising Professors: Kevin Caves and Richard Goldberg
INTRODUCTION
Our client Mia is a 6-year old girl with pituitary dwarfism who expressed interest in learning to play a stringed instrument. Her fingers are all on the order of 1 inch in length and she has range and strength limitations in her hands. As a result, while she can produce a pinch grip, she cannot press individual strings on an instrument.
We modified a sopranino size ukulele that allows Mia to selectively hold down the strings in between the frets using the gripping force of her fingers. The device consists of five pivoting keys that can individually be depressed by pulling down on attached thumbscrews. We chose to work with a ukulele since it weighs less and is smaller than a guitar, and because it is played on the lap, it was easier for the client to hold than a violin.
Figure 1: Photo of the Ukulele Hero device
STATEMENT OF IMPACT
Our advisor, an occupational therapist, indicated in a survey that she was satisfied with the overall design, and was impressed by our success in tailoring the device to fit our client’s needs. She stated, “We have had to problem solve and really adapt for her finger abilities, for her stature, and her range of motion. I think it’s been an awesome piece to see the design of it and the functional use of it and how she’ll be able to enjoy playing music.” Furthermore, our client’s mother also reflected that she was very satisfied, and agreed that the team was attentive to our client’s abilities and open to new ideas.
TECHNICAL DESCRIPTION
The main modification to the ukulele is the addition of spring-loaded keys, which act as capos to change cords. These are supported by a dowel and guide wire, and attached to the ukulele by connecting to a polypropylene thermoplastic chassis that is molded to the curvature of the instrument. We also added a commercially available guitar strap that fits over a custom-mounted end pin. We tuned the ukulele to an open chord, which means that strumming on all four strings produces a chord when no strings are pressed on the frets.
The client changes the chord by lowering a key across a row of strings. This is accomplished when she pulls on thumbscrews attached to the keys at the far edge of the neck. The keys are made from Delrin plastic, and are mounted to the support dowel that runs through two mounting blocks that are fitted into the pockets of the thermoplastic cast, one at the bottom of the neck and the other at the top. Small torsion springs threaded through holes in the dowel and keys serve to raise the keys off the strings when not depressed. A guide wire runs through the mounting blocks above the dowel and prevents the keys from springing up too far, which would make it difficult for Mia to activate them. The design also includes a 23” child size strap tied through the top of the ukulele neck and affixed to a pin at the bottom of the instrument, allowing equal weight distribution so that Mia can hold it easily.
Figure 2: Client with the Ukulele Hero device
The modification acts as a lightweight interface between our client and the instrument, and is rigidly attached to the ukulele neck so as not to require removal. It is slim and durable, and can be easily carried to and from school, music lessons, or wherever else Mia would like to take it. Each key was evaluated in three trials, the result being that 88% of the time our client pulled the keys down, all the strings were hit. This allows her to play different notes easily and pursue her interest in music.
The total cost of this device is $125.