FOM: Palpable Point Pixel device

Neil Tennant neilt at
Mon Apr 30 10:14:11 EDT 2001

I had a blind student taking Logic two years ago. We found there was
*nothing* out there to help the blind learn logic. So I made a "logic
board", which was a piece of 3-ply (8' by 4') covered with felt and with a
support system that would hold it at an angle on a table. Then we had
brass dyes made, of all the logic symbols that would be needed, from a
LaTeX prinout. (This was the expensive bit---about $1000 was spent on
this.) With those dyes, we stamped out many sheets of embossed symbols.
The individual tokens were then cut out, and backed with Velcro. Each
token was about 1.5" square. We had a rough logico-alphabetical ordering
of groups of symbol-tokens round the periphery of the board, and the
student could then construct his formulae and natural deductions in the
middle of the board. 

Braille is simply too limited to generate all the logical symbols.
Moreover, it's essentially linear. With the 2D logic board, by
contrast, the student could use touch *and* proprioception as
clues to global logical structure. The sighted instructor can also close
his/her eyes and try to "read" an embossed natural deduction, thereby
getting a good sense of what the blind student is up against.

I also invented what is called the "Palpable Point Pixel device", on which
OSU's Office of Technology Transfer has all the documentation establishing
legal ownership of the idea. I visited six local high-tech engineering
firms to try to persuade them to build a prototype, but, sadly, the profit
motive and their worry about the size of the potential market were both
inhibiting. (There are "only" about half a million blind people in the USA
who would benefit from the PPP-device.)

The PPP-device is based on the idea that where a computer screen has a
pixel of light, there could instead be a thin metal rod that could
protrude and retract, with its level of protrusion proportional to the
intensity of the light pixel. It is definitely feasible from the
engineering point of view, using Piezo electronics, which convert current
into displacement of material.

The PPP-device would allow the blind person to scroll, zoom in and zoom
out, palpate *any* image that can be rendered in a 3D fashion (such as pie
charts, histograms, etc.), and, most importantly, have full veridical
access to mathematical symbols as used by the sighted. It would also allow
on-line interaction between teacher and blind student(s), with the
student(s) being able to follow, literally hands-on, what the teacher is
writing at that very moment. (Current alternative  methods are hopeless in
this regard.)

If you or any member of this list could put me in touch with a willing
developer of such a prototype device, please let me know. There could be
many blind potential logicians (not to mention mathematicians,
statisticians etc.) who are lost to the profession for want of a basic
medium of communication.


Neil W. Tennant
Professor of Philosophy and Adjunct Professor of Cognitive Science
230 North Oval
The Ohio State University

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