A Low-Fidelity Prototyping Method for Blind Users: A Case Study on Designing Two-Dimensional Tactile Displays
Sara Alzalabny, Karin Müller, Kathrin Gerling, Thorsten Schwarz, Bastian Rapp, Rainer Stiefelhagen · 2025 · ASSETS 2025: 27th International ACM SIGACCESS Conference on Computers and Accessibility · doi:10.1145/3663547.3746397
Summary
This paper addresses the fundamental problem that design workshops—a key method for involving end users in technology development—are largely inaccessible to blind people due to their reliance on visual methods like sketching, storyboarding, and visual prototyping. The researchers developed an adapted low-fidelity prototyping method specifically designed to enable blind participants to actively contribute to the early-stage design of assistive devices, using the development of a 2D tactile display as a case study. The research was conducted in two phases. In Phase I, four individual co-design workshops with blind participants iteratively refined a haptic prototyping toolkit and workshop structure. The resulting toolkit includes 3D-printed buttons and control elements with tactile markings, a magnetic box representing the device case with magnetic surfaces on all sides, a printed list of features in Braille, and embossed tactile screenshots of software UIs. In Phase II, six prototyping workshops with 12 blind participants (11 totally blind, one with severe low vision) tested the refined method. Each workshop paired two blind participants with two sighted assistants and a moderator, incorporating individual design sessions (45 minutes in separate rooms) followed by a collaborative session (30 minutes) where participants merged their best ideas into a shared prototype. The approach successfully enabled blind participants to create functional prototypes and generate creative design ideas beyond the predefined feature set.
Key findings
The study produced several important findings about accessible prototyping: (1) The magnetic-based toolkit was highly intuitive—participants could quickly place, move, and iterate on designs without extensive instruction, with 3D-printed elements preferred over clay for their realistic feel and precise shapes. (2) Workshop structure matters as much as materials: individual sessions before collaborative ones allowed participants to develop independent ideas without being influenced by others, and the small group size of two prevented dominant voices from overshadowing contributions. (3) Embossed paper representations of software UIs were critical for participants to understand and design for digital interfaces, bridging the gap between physical prototyping and software design. (4) Seating arrangement significantly impacted collaboration—corner seating in collaborative sessions enabled participants to physically guide each other's hands to prototype features. (5) The role of sighted assistants was complex: they were essential for explaining unfamiliar concepts and documenting designs, but had to maintain strict neutrality to avoid biasing participants' decisions. Even minimal feedback like affirming murmurs could influence design choices. (6) Participants generated creative ideas beyond the predefined features, including customizable multi-functional buttons, left/right-handed controls, virtual keyboards, and a centralized platform concept for 2D tactile display applications. The paper provides four categories of concrete recommendations covering materials, workshop structure, environment, and assistant roles.
Relevance
This research makes a practical contribution to inclusive design methodology by demonstrating that low-fidelity prototyping—traditionally one of the most visually dependent design activities—can be effectively adapted for blind participants. The toolkit and workshop structure are transferable beyond tactile displays to other hardware design contexts where blind users need to prototype tangible interfaces (e.g., Braille keyboards, wearable devices). The findings about sighted assistants are particularly valuable: the tension between providing necessary support and avoiding bias is a challenge in any co-design process involving disabled participants and non-disabled facilitators. The recommendation to limit assistants to neutral, factual support and avoid expressing opinions—even inadvertently through tone—provides actionable guidance for researchers conducting accessible design workshops. The work also highlights that accessible co-design requires holistic adaptation of the entire workshop experience, not just swapping visual materials for tactile ones.
Tags: blindness · low vision · prototyping · co-design · tactile display · design workshops · assistive technology design · participatory design · haptic interaction