‘D-Lite’: Ergonomic Lighter

CAD Model
January - February 2024

How can candle lighters balance inclusive, intuitive design with safety?

Candles have become a subject of modern ritual. Whether it be creating serenity within a dorm room, serving as a symbol in religious custom, or literally lighting the way when the power cuts out, the act of lighting a candle holds significance beyond its functionality. However, the current design of the lighter’s handle prioritizes safety at the expense of inclusivity, as users with limited mobility often struggle to hold down the safety button while lighting a lighter. We used ergonomic heuristics to redesign the candle lighter to allow for minimal wrist and finger strain to make it easier on those with less hand strength.

Skills:

Fusion 360 CAD
Foam Modeling
User Testing
RULA Assessments
Ergonomic Design

Task Analysis

Concept Sketches

Initial Sketches:

Benchmarking and User Testing

Iteration 1:

1

Pear-shaped

Foam Model Testing Takeaways:

Fit awkwardly in users’ palms
Proportions are off, too small
Shape doesn’t provide secure grip

2

“Mouse” Model

Foam Model Testing Takeaways:

Too wide for users with smaller hands
Thumb indent made contact with the palm extra comfortable
Users worried it would be too heavy dependent on the material

Iteration 2

1

Front-Button Handle

Foam Model Testing Takeaways:

Users’ favorite of all models thus far
Having the button in the front felt most intuitive
Really enjoyed finger divots
Wished it was a bit longer for larger-handed people

User A Evaluation: Small Hand, F

User B Evaluation: Medium Hand, M

User C Evaluation: Large Hand, M

2

Wrap Around Side Button

Foam Model Testing
Takeaways:

Didn’t find grip as comfortable as the previous one
Too small for User C’s hand
Wished there was a finger diver between the pinky and ring finger
Lower average rating than the previous prototype

User A Evaluation: Small Hand, F

User B Evaluation: Medium Hand, M

User C Evaluation: Large Hand, M

Moving Forward

I decided to move forward with the front-button handle, as it scored the highest for comfort, modifying it to have a longer handle and larger finger divots to accomodate larger hand size.

Final CAD

Reflections

During this project, I was forced to think critically about the intersection of safety, accessibility, and comfort when redesigning a common, but potentially dangerous household product.

Practiced using Stanford’s Product Realization Lab hot wire cutter to create physical foam models
Created 1:1 orthographic sketches to assist in prototype making
Tested with “edge-case” users to ensure the product worked comfortably for a large range of hand sizes
Used heuristic data to parametrize final CAD
Thought critically about material as it pertained to grip, and grip’s importance