StretchAR
The Problem
The variability of body shapes, activities, and priorities for users make challenging the creation of a one design fits all method of interaction for smart glasses. Current approaches are either obstructive, complicated, exhaustive, or not socially adequate.
StretchAR explores the design space of stretchable smart straps as an input modality for human-AR interfaces to enable fast and eye-free interaction between wearers and their smart glasses.
The project describes the development and evaluation of StretchAR, a unisex smart accessory designed to be worn by users with different body types and attachable to a large variety of outfits.
My Roll
I was the lead researcher of this project and my main tasks were:
Run
evaluations and interviews with participants
Design
and implement a touch-stretch wearable sensor
Identify
preferred methods of interaction and applications
Design
user studies protocol to evaluate users interacting with smart glasses through StretchAR
Analyze
Qualitative and quantitative data to generate guidelines for design and manufacturing
StretchAR Strap Design
StretchAR is a strap-like wearable capable of simultaneously detecting touch and stretch input modalities. We designed StretchAR as a lightweight and stretchable strap to enhance its conformability, wearability, and allow single-hand manipulations. The thin geometry of StretchAR facilitates the integration of the stretch-touch interaction modality into multiple body locations and garments.
Example Applications
The example applications were developed to illustrate and demonstrate the feasibility and applicability of FabHandWear.
The models focus on different hand features to illustrate why hands need special treatment compared to other parts of the body. Inspired by real-
world, health, aesthetics, and sci-fi applications, the designs show customized hand wearables to monitor health, cosplay, or interactions with emerging technologies.
Evaluation Methodology
We conducted a user study to determine the feasibility, usability, and accuracy of StretchAR as an interaction method for smart glasses and HMD.
We systematically evaluated the study results to define the interaction modality and elicit design guidelines that will allow StretchAR to succeed as a form of interaction.
The study had 3 parts: a) Task 1 - Touch & stretch interactions, b) Task 2 - Touch & scroll interactions, and c) an elicitation interview.
Task 1 - Touch & stretch interactions
Independent Variables
​
- 4 body location (Head, Chest, Forearm, Wrist)
- 3 number of fingers (1,2,3)
- 4 sphere positions (0, 25, 50, 75, 100%)​
36 trials for each Body part to generate a total of 144 trials for each participant
Task 1 assesses the influence of body location, the number of fingers, and the level of applied stretch on the accuracy with which the user interacts with an AR target using StretchAR.
Task 2 - Touch & scroll interactions
Independent Variables
​
- 4 body location (Head, Chest, Forearm, Wrist)
- 3 number of fingers (1,2,3)
- 2 scroll directions (Up, Down)
18 trials for each Body part to generate a total of 72 trials for each participant
Task 2 aims to assess the influence of the four proposed body locations, the number of fingers, and the scroll/swipe direction on the performance and accuracy of the user while using StretchAR to interact with a virtual rotational menu.
15 participants (6F/9M) - Ages 21 to 28 years old (mean 23,1, SD 2.4)
At the end of the study, each participant took a conversation-type interview to provide subjective feedback, interaction suggestions, and share their vision for future StretchAR applications.
Data collection:
a) Video recording (screen capture) - To store process, errors, and time.
b) Head-mounted display (HMD) data - time, task completion.
c) Post-survey - NASA TLX, willingness to use (0–100) scale, and convenience level (0–10) scale.
d) Interview video recording
Lessons learned
96% accuracy using stretch-touch interactions with smart glasses
Defined 28 stretch-touch interaction modes for smart glasses
Identification of 36 types of stretch-touch applications
No statistical difference in usability or preference across 4 body locations
Defined design and fabrication guidelines for stretch-touch interactions with smart glasses