Poly Edge e500 Series

Team Composition:

2 Design Engineer Researchers

Role:

Lead HF

Problem

When designing the handheld device, several key ergonomic challenges needed to be addressed to ensure comfort and functionality during use:

Finger/Button Clearance: Ensuring that users’ fingers could easily reach and press buttons without interference or discomfort, especially during extended use.
D-pad Travel and Button Force: The D-pad and buttons required careful calibration of travel distance and button force to ensure smooth operation and tactile feedback without straining the user’s fingers.
Knuckle Clearance: Adequate clearance around the knuckles was essential for users to hold the device comfortably without obstructing their grip or causing discomfort during long gaming sessions or use.

Usability Test 1

Using a high-fidelity prototype, I compared button spacing and sizes against the 5th, 50th, and 95th percentile index finger sizes. I conducted an initial usability test, evaluating the design using my own hands and fingers. During this test, I analyzed:

Button spacing
Button travel forces
Button sizes
Hand clearance on the handheld device

This helped me assess the overall comfort and ease of use, ensuring the device was ergonomically sound for various finger sizes.

Usability Test 2

For the second iteration, I tested three versions of the D-pad, each with different button travel heights and edge grooves. The test revealed that users with a 95th percentile index finger size experienced accidental presses of the back and home buttons, located on each side of the D-pad, simultaneously.

By adjusting the grooves on the D-pad and increasing the button travel, I was able to create more space for the fingers and reduce unintentional presses of nearby buttons. These adjustments improved the usability for users with larger hands.

Usability Test 3

In the final usability test, I simulated a use case where users would interact with the device while wearing gloves. I tested users with the 5th, 50th, and 95th percentile index fingers wearing three different glove thicknesses: thin, medium, and thick.

The results showed a significant decrease in space between buttons, leading to accidental presses of adjacent buttons, particularly for users with the 95th percentile hand size when wearing thicker gloves. This highlighted the need for more spacing between buttons or alternative design adjustments to accommodate gloved use.

For more details on this project, please contact me.

lopezg7575@gmail.com

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