Facade: Auto-generating Tactile Interfaces to Appliances
Anhong Guo, Jeeeun Kim, Xiang "Anthony" Chen, Tom Yeh, Scott E. Hudson, Jennifer Mankoff, Jeffrey P. Bigham · 2017 · Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems (CHI 2017) · doi:10.1145/3025453.3025845
Summary
This paper introduces Facade, a crowdsourced fabrication pipeline that enables blind people to independently make flat-panel appliance interfaces accessible by generating 3D-printed tactile button overlays. The problem addressed is that modern appliances have shifted from physical buttons with distinct shapes to flat touchpads, making them inaccessible to blind users who cannot visually identify controls. While blind people can apply Braille stickers, this typically requires sighted assistance to identify button functions and place labels correctly, and the stickers fall off over time. Facade works through a multi-step pipeline: a blind user photographs the appliance interface alongside a dollar bill (used as a fiducial marker for size recovery and perspective transformation), crowd workers on Mechanical Turk segment the interface region and label each button, the blind user customizes labeling preferences (Braille, embossed letters, or symbols) through an accessible iOS app, and an OpenJSCAD script automatically generates a 3D model of pressable tactile buttons that overlay the original controls. The overlay is fabricated on a home 3D printer or ordered from a commercial service for under , then attached with adhesive by the blind user. The system went through three design iterations, exploring materials (PLA, NinjaFlex, SemiFlex) and labeling approaches to optimize attachability, legibility, and pressability.
Key findings
In a user study with 11 blind participants (ages 40-82), Facade proved viable across all pipeline stages. Participants attached the dollar bill fiducial marker in 30.3 seconds on average and rated it very easy (4.8/5). Photo capture averaged 33.6 seconds per image, rated neutral difficulty (3.2/5). Overlay attachment took 117.1 seconds with 9 of 11 participants succeeding (rated 3.8/5). For button identification, 10 participants chose Braille and achieved 98.3% accuracy reading all 25 microwave buttons in an average of 112.6 seconds. Button location tasks achieved 97.3% accuracy with an average of 6.7 seconds per button. Simulated cooking tasks were completed with 92.5% accuracy in 17.2 seconds average. The crowdsourcing workflow was fast (8 minutes for segmenting and labeling) and inexpensive (.15 total). The perspective transformation component successfully warped 61.8% of photos taken with the Facade app. Participants strongly preferred Facade over traditional Braille stickers, commenting "I like [Facade] much better. I can do it myself" and "If template gets damaged, then I can create a new one." The system was tested across microwaves, refrigerators, and copiers, demonstrating generalizability across appliance types.
Relevance
Facade addresses a practical, everyday accessibility problem that affects millions of blind people: the inability to independently use flat-panel appliances in homes, workplaces, and public spaces. The approach is innovative in combining three technologies — computer vision, crowdsourcing, and 3D printing — into a pipeline that a blind person can operate without sighted assistance. For accessibility practitioners, the formative study findings are particularly valuable: blind users want independence in labeling appliances, prefer different reading mediums and labeling strategies (not everyone reads Braille), and need solutions that are reproducible when labels wear out. The design insight of using different button shapes for different function types (rectangular for functions, spherical for numbers) shows how tactile design conventions can encode information beyond simple labels. As consumer 3D printers become more affordable and printing services more accessible, Facade-style approaches could become practical solutions for making legacy physical interfaces accessible, complementing the growing trend of smart home devices with accessible digital interfaces.
Tags: 3D printing · tactile interface · blind users · crowdsourcing · fabrication · appliance accessibility · assistive technology