Online

Shuster, Samuel B. F.

Mechanical Engineering

2018

MS

Students who are blind or have low-vision (BLV) do not have the same access to graphical curricular content as their sighted peers. This significantly affects their education, particularly in STEM subjects. Introduction of interactive tactile graphics is one of the only ways for BLV students to access graphical content, and is uniquely suited to teaching drawing skills. The goal of this engineering design project was to expand the capacity of printing technology that produces interactive raised-line graphics by creating a system to print textures that meet specific criteria for usefulness. The addition of textures to tactile graphics is essential for the graphics to be unambiguous and to communicate information about spaces and regions. Maps, geometric figures and graphs are prime examples. The system developed in this project for printing tactile textures was designed as an enhancement of an existing beta prototype printer for interactive tactile graphics co-developed at UVM and E.A.S.Y. LLC. Preliminary experimentation indicated that varying the size of the drawing stylus tip would afford the greatest range of printed textures. Based on this finding, the Texture Creation System (TCS) was designed with this new functionality. This thesis describes the process by which the categories of possible designs were refined and how the TCS - based on a system of interchangeable self-locking tapered tips - was designed, built, revised, and tested. We developed a set of six tactile textures (the Texture Set) as examples of the capabilities of the TCS. We then designed and performed an experiment in which six BLV subjects assessed the textures based on their Distinctness, Recognizability, and Variability in Degree. In all tests that mimic real-world use, the Texture Set was found to be successful in at least 75% of trials. The design also successfully addressed constraints for speed of operation, system cost, noise volume, and compatibility with the beta printer. The design also met standards for reliability and mechanical strength. Future engineering will be required to add sensors to monitor mechanical operation. Also, larger-scale user testing of the Texture Set (and other textures) will be needed for statistical significance and to provide insight into what objective properties of the textures elicit certain subjective responses, i.e. why certain textures meet design criteria better than others.