Assistive Technology Devices
Designed and 3D-printed assistive devices (vegetable slicer, bag closer, iPad holder) under one-handed usability, single-print fabrication, and safety constraints. CAD, rapid prototyping, and iterative user testing.
Background
This project was conducted through ASME in collaboration with the Illinois Assistive Technology Program (IATP). The objective was to design devices for users who perform everyday tasks with one hand.
Design Constraints
Each device had to satisfy the following requirements:
- Fully operable with one hand — including setup, use, and cleanup
- 3D-printable in a single print — no multi-part assemblies or fasteners
- Reasonable print time (under approximately 4 hours on a consumer printer)
- Lightweight, for users with limited grip strength
- Safe — no pinch points, sharp edges, or unstable positions during use
Devices
One-hand vegetable slicer. Holds produce against a cutting surface so the user can slice single-handed. The first prototype secured the vegetable but was difficult to load with one hand — the user had to push it into a clamp, requiring a second hand to stabilize. The design was revised to use a gravity-assisted loading channel where the vegetable is dropped in from above and secured by a spring-loaded holder.
Ziplock bag closer. Allows a user to open and seal a ziplock bag with one hand. The difficulty is that ziplock bags are flexible and cannot be sealed without holding both sides. A channel was designed to hold the bag open and guide the seal closed in a single sliding motion.
iPad holder. Supports an iPad with one-handed insertion and release. The device holds the iPad at a usable angle while allowing removal without a two-handed grip. A friction-fit cradle with a thumb-operated release tab was used.
Process
I worked with the ASME project lead and the IATP project manager to define requirements, then iterated through CAD models and printed prototypes. Each design went through multiple rounds of testing against the constraint list. In some cases, a design that passed the usability test failed the single-print constraint because it required support structures that made the geometry unprintable. Geometries, wall thicknesses, and tolerances were adjusted to satisfy all constraints simultaneously.