MOUTHSTICK...
... Designing for a better lifestyle
WHAT
An extendable device which users can bite down on and use to interact with their environment (e.g. flick light switches, press elevator buttons, or operate home appliances), including touch-screen technology with an integrated conductive tip.
WHY
To enable everyday accessibility for patients with quadriplegia.
WHO
Team of 2 - 4 Manufacturing & Design interns
WHEN
Summer 2019
IN NEED OF A REPLACEMENT
Brandon (left) and I met Ken (middle) after he had reached out to Northwestern University through the Shirley-Ryan Ability Lab.
Ken’s old device was starting to wear and he one that was lighter and more durable.
Professor Kelso (Biomedical Engineering department) had built a mockup for us to test and improve. Using the following materials:
- Aluminum sheet (0.1 in. thick)
- Aluminum tube (hollow)
- Carbon fiber tube (0.25 in. d.)
- Tygon tubing
- Clamping collars
- Conductive plugs
Brandon and I constructed a new mouthstick that would last longer and be easier for Ken to use.
3 PAIN POINTS
Ken identified the mouthpiece, shaft collars, and stylus as the areas of improvement in the initial mockup (shown below).
The mouthpiece needed to be longer and wider.
The shaft collars needed to be smaller.
The stylus needed to be robust.
My primary roles were:
- Redesigning the mouthpiece
- Redesigning & mocking up collars and stylus
- Selecting & ordering materials
Brandon and I scheduled meetings with Ken after every iteration to test mouthpiece sizes and angles, shaft collar sizes, and stylus visibility and responsiveness.
THE DIFFERENCE
Stylus & Shaft Collars
We replaced the plastic collars with adjustable-width shaft collars for mounting on wheelchair & controlling length of shaft. Advantage of adjustable width feature is adapting the device to different mount thicknesses.
We replaced the fabric & copper wire stylus with a thick metal-mesh conductive plug for interaction with touch-screen technology. The plugs are more durable and allow for a simpler, sleeker design.
Telescoping
We replaced the old clamp with a simple pipe clamp that can be adjusted with a flat screwdriver.
We used carbon fiber as the inner tube for smoother surface interaction with the aluminum rod. It also provides added resistance to fracturing, providing a more long-lasting design.
Mouthpiece
We simplified the design of the mouthpiece using Adobe Illustrator then cut it out using the waterjet.
A set screw secures the mouthpiece to the aluminum rod allowing for easy replacement.
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