ergonomic screwdriver
Timeline
Jan - Feb 2020
Context
Team Project, Stanford Product Design Class
Contribution
User Testing
Design Sketching
3D Modeling
Project Overview
My team was tasked with improving the ergonomics of an existing hand tool. We selected the classic manual screwdriver, analyzing it from a bio-mechanics and anthropometrics perspective.
01 Design Challenge
How can we create a screwdriver that is more ergonomic?
02TASK ANALYSIS.
We watched users screwing a screw, deconstructing it into each movement and posture required. We discovered human factors issues:
  • User must adopt a pinch grip while applying force
  • Small diameter of the tool requires excess twisting at the wrist
  • Disproportionate pressure where hand makes contact with tool
  • Dominant hand must apply forces in different directions
Diagram of Findings
03design requirements
  • Lightweight. Can be used away from the body
  • Sturdy. Maximizes grip strength
  • Adaptable. Suits a wide range of hand sizes
  • Comfortable. Keeps the wrist neutral and minimizes arm abduction
04sketching
Exploring concepts that apply the design requirements. As a team, we came up with 30 designs total. Here are some of mine:
05User Testing
We created low-fi prototypes out of foam for our six favorite designs. We presented them to users, asking them to mimic the movement of unscrewing a screw.
We analyzed people's use with analytical methods like Rapid Upper Limb Assessment (RULA) and body mapping surveys. We also heard direct feedback in a short interview.
Example Notes from Tests
06Refining Ideas
We sketched new designs and made 6 more foam prototypes.
07further usability testing
From testing our 6 new prototypes, it was clear that this 2-handed, oblong-shaped grip came out on top: 
10 Final render
I created these CAD models to show how the insights from the second round of user testing were integrated into the final design of the screwdriver. (Click images to view full screen.)