Graph literacy is essential to STEM education, yet visually impaired (VI) students face persistent barriers not only in interpreting graphs but also in creating them. Existing tactile tools often offer limited layouts, inconsistent feedback, or require sighted assistance. This restricts opportunities for independent graph authoring. In Thailand, imported embossers and printers are costly and scarce, while low-tech alternatives lack portability and tactile precision. This study developed a low-cost, roller-based graph-paper embosser through a three-iteration User-Centered Design (UCD) process. The tool embosses XY coordinate planes onto A4 paper, allowing VI students to plot points and construct graphs independently. Design iterations were informed by surveys of existing tactile graphing tools and refined through feedback from VI students and their teachers. The final prototype featured a microfiber-lined embossing surface, a compact grooved roller, and a plus-sign XY guide for alignment. Usability testing with 40 VI students combined task metrics, satisfaction ratings, and qualitative feedback. Participants reported improved tactile clarity, quadrant orientation, and confidence in graph plotting. In performance tasks, 57.5% of students accurately completed 9-12 graphs, demonstrating the tool's instructional effectiveness. By emphasising tactile-only interaction, iterative refinement, and teacher collaboration, this study offers a scalable model for inclusive STEM learning. It contributes to the development of accessible educational tools that empower VI students to author graphs independently, reduce reliance on sighted assistance, and promote equitable participation in mathematics education.
Traitruengsakul et al. (Thu,) studied this question.