Some previous studies has shown that zooming and panning can increase the understanding of tactile graphics. As our tactile device not only outputs raised dots it can also provide touch input(s) matrix, we can implement multi-touch touch gesture recognition activities, similar to an android phone. We can use these touch gestures to make our system more inteactive. As a very simple example, consider a student who is trying to learn about a polygon. Given the situation that only static polygon is being displayed on the tactile device it would be tough for the blind student to interpret and learn about the polygon. Now, if we add various multi-touch functionalities such as zoomin and panning, it would be easier for the blind student to learn about that polygon.
Synchronization of synthetic voice with various elements of polygon make our platform more interactive. For instance suppose if the blind student wants to go over some specific information about the polygon then he would need to just single-tap/double-tap corresponding element (Edge/Angle) of the polygon on the tactile device and synthetic voice would provide the description of what is touched.
Similarly to the above example of polygon, we can use special dynamic renderings to display and teach about tougher concepts. For example, circular waves can be displayed using vibrating concentric circles emanating outward from the center. A projectile motion can be displayed by animated patterns depicting trajectory of the projectile.

All the braille tactile devices available in the market now a days are very expensive. For exmaple, the tactile device which is available in the lab is very expensive (costs around $5000 USD) and it has very limited resolution (24X15 pins). To overcome the resolution and cost problem, we have integrated it with encoder aided mechanical XY-slider with central stage having moving capacity of 50 cm X 50 cm. Now the effective resolution of 200X200 dots. A braille device with 200X200 dots should cost around $450,000 but the overall system (XY-slider + Tactile device) now costs only around $8,000.

An important aspect of this project is to create an open-source, high-quality typesetting system for automatic trancription of STEM books into braille. Learning resources for blind people are quite sparse and trancription of STEM material is very expensive and time consuming procedure. For example, transcription of a math textbook takes around several months and it costs more than $100,000. With our auromated open-source coding platform it would be quite easy, fast and inexpensive for publisher to transcribe various STEM books. The scope of this automated transcription plateform is not only limited to STEM books but it can be used for trancription of any content/book/webpage available online. Snapshot of current version of this typesetting system is depicted below.

The ultimate goal of this project could be considered as to create Ipad kind of highly intuitive tough-capable display to help blind and visually impaired. Though we have just started developing this platform, we strongly believe that the outcome of this project could be a fundamental advance in STEM accessibility for blind and visually impaired people.

This video sequence can be downloaded here

Low-Cost, High-Resolution Tactile Display

Some members of our MIT-Fifth Sense project team are also working with some collaborators from Northeastern university and are building a compact, scalable, high-resolution (with 2000-4000 vibrating pins), MEMS-enabled low-cost tactile display. A preliminary version of this device with 28 vibrating tactile pins has already been develped. An image of this device is on the left.

The pins in this tactile device would be driven by a piezoelectric extension actuator that elongates and shrinks horizontally when diffrent voltages are applied between uppper and lower surface. Using a simplified scissor mechanism the horizontal motion of peizoelectric extension actuator is converted to vertical motion to emulate vertical braille pins in the tactile display. When an appropriate oscillating voltage is applied on the upper and lower surface of actuator the pins vibrate up and down. A blind user can sense the virations by touchind these pins. The experience of feeling the vibrating would be similar to that experienced in an Optacon. However, the proposed hardware which we are developing would be >20x in resolution and would be low-cost.

a) Tactel diagram showing actuator (red) plus amplifier (light blue) structure in the unactuated (top) and actuated (bottom) positions. b) Two tactels with pins and cap plate. c) Small array of tactels shown organized in an offset array without pins or cap plate.


[1] X. Xie, Y. Zaitsev, L. F. Velasquez-Garcia, S. Teller, and C. Livermore. compact, scalable, high-resolution, MEMS-enabled tactile displays. (under review)