Hi David. Considerable research was done during Dr. Tim Cranmer's day (or
was it Cramner?), and also in Israel regarding a multi-finger optacon. The
results showed that a single finger worked best. Having a display that was
shaped so it could accomodate several fingers made no improvement in
reading, speed or extended reading session.
Charles
-----Original Message-----
From: David
Sent: Wednesday, June 03, 2015 4:22 PM
To: optacon-l@xxxxxxxxxxxxx
Subject: [optacon-l] Single- or Multi-finger display. Was: Re: More frame
designs
I sure appreciate all the research and Pre-production work being done on
a followup Optacon. If you want some testing, and it can be done
off-site (am unable to travel), please contact me off-list:
trailerdavid@xxxxxxxxxxx
Yet, one tiny point to make, in connection with your alternatives for
display models. One of the big advantages I find with the Optacon, is
its SINGLE-FINGER design. First, long-term reading causes fattigue, and
swapping fingers have been a real saver for me. Second, if you are
designing something that requires multi-finger recognition,what then
with people who has damaged one of the required fingers? Even if I cut
my one finger, and it is one of the three your design relies on? Even a
standard Braille display can be read with just one finger, should the
user be limited. An Optacon, designed to rely on more than one finger,
may seem great in the first token - since you then can display higher
amount of info simultaneously. Yet I dare claim it soon will prove
little effective, and limit its own market value.
Thirdly, I have tested equipment earlier years, that depended on
multi-finger operation. Trouble was to interpret signals from all
fingers at the same time, and coordinate them in your brain. I thought
it was me, so I let a couple of students and others test it as well, and
they reported same issue. OK, it was more of a Braille mouse product, so
not exactly the Optacon. Still, I know there has been other products
that based their activity on multi-finger reading, and honestly, have
not seen any of them make it to the market.
About a year ago - or something like that - there was a discussion on
this very list, where the question came up: Which hand/finger do you use
to read Braille. Funny how many reported that they had one MAIN finger
for reading Braille. The rest of the fingers are more used for
coordinating and positioning on the paper. Just to back up my point:
If you base your display on more than one finger, you are likely
restricting your product out of the main market. Few people may be able
to do the mental/sensitivity acrobatics of making sufficient usage of it.
Also, be aware of a lot of people who are blinded at a grown-up age, and
who will have their full day busied, just to train enough sensitivity in
one finger.
My real-life based advice, for you and any other developer, is to keep
the display for ONE-FINGER reading. It definitely will give the product
the highest tayloring chance, and serve the most users' interests.
David
On 6/2/2015 6:15 PM, reinoud wrote:
More frame designs, this time some lower cost options, images can be found
here: https://tactact.wordpress.com/2015/06/01/frame-design-5/
These frames consist of one part, typically made of plastic, with
actuators mounted directly below the finger plate. This way they can be
relatively low cost and low profile. Compact coils are used like with the
previously shown high-res display, and they aren't necessarily limited to
low power operation despite being mounted in plastic, as explained below.
The first example (tctct2-frame-open-mini.png) accomodates a 10x16 array
of 160 pins in roughly the same finger plate area as the standard Optacon
display. With a horizontal pitch of 1.5mm and a vertical pitch of 1.8mm,
this layout is not really appropriate for Optacon-like reading use
(vertical resolution is relatively low) but it may be an attractive
alternative for the 'mobile' version proposed before. Smaller versions
with lower vertical resolution (e.g. 10x10, 100 pins, just covering a
fingertip) may be more suitable for low cost and low power applications.
Disadvantages of this first design are resolution and power limitations,
and high precision manufacturing requirements due to the actuator packing
density. Also, interconnect cost will be high because of the curved
actuator array without a common node available, requiring two connections
per actuator.
The next design (tctct2-frame-open-mini-wide.png) improves resolution by
increasing width rather than height, intended for use with more than one
finger at a time. The example in the image has the same pin pitch as
before but has a less curved finger plate and is rotated 90 degrees. With
28x14 pins at 1.8x1.5mm it provides for 392 pins on a 48.6x19.5mm active
area, usually enough for 3 fingertips.
This arrangement has several advantages besides an obvious higher overall
resolution. Pin pitch is smaller in vertical direction now (like Optacon
displays), and even though the density is lower than an Optacon display it
covers a larger total area, all of which consists of the most sensitive
part of fingertips. Because of this I expect this display to perform quite
well at lower power and frequencies. Like the previous design, it still
requires a high precision plastic part and interconnect cost will be high.
Cost (including precision and interconnect requirements) can be brought
down by moving to a flat lower density display as shown in the third image
(tctct2-frame-open-mini-flat.png). This example has a 24x10 array of 240
pins on a 46x18mm active area display similar to the previous one. The
lower density allows for somewhat higher efficiency coils, mounted on a
lower precision, more heat resistant plastic frame, which allows driving
at high power. Also, with actuators mounted in a flat plane coil contacts
can be made to fit a printed circuit board below to simplify assembly.
This last frame design is quite a departure from the Optacon standard
layout but seems promising: it is relatively high resolution yet low cost,
suitable for high and low power modes, and has a simple low profile
construction.
I am calculating costs for the various designs, will post on that soon!
Signatures for reference:
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