TactionTablet : affordable tactile graphics display

Abstract

This thesis presents the design and manufacture of a new type of refreshable tactile graphics display at a drastically lower cost than existing options. The device, now called the '"TactionTablet", uses a single actuator attached to a two-dimensional plotter to raise a grid of individual bumps that lock in place above the tablet surface to form a graphic that can be explored by touch at the user's own pace. The TactionTablet was designed to be built using the tools and supplies available in typical hardware stores and makerspaces, allowing it to be used as a practice project for equipment training. The core innovation of the device is the evolution from traditional displays using multiple active electronic actuators to a single mobile actuator controlling many passive pins. While this new mechanism is much slower than that of a traditional display, it is also cheaper to produce by multiple orders of magnitude, as adding more pixels does not increase mechanical or electrical complexity. This effectively removes the financial barrier of entry to tactile displays. The final prototype display produced in this thesis has sufficient resolution to display graphics up to 28 by 29 pixels in size, while being simple enough to build in any makerspace. The plotter mechanism's accuracy and speed are lower than expected, taking two minutes to display a typical graphic, but the ultra low material cost of $32.07 places the device in a class of its own. One complete device has been manufactured during this thesis and all mechanisms validated. In the future the design can be further miniaturized with injection molded pins or a more sophisticated plotter to achieve higher resolutions and likely display braille.