[optacon-l] Re: For anyone familiar with the optacons research and design

From: Richard Vickery <Richard.Vickery@xxxxxxxxxxx>
To: <optacon-l@xxxxxxxxxxxxx>, optacon-l digest users <ecartis@xxxxxxxxxxxxx>
Date: Sun, 13 Apr 2014 16:27:00 +1000

On 13/04/2014 3:10 PM, FreeLists Mailing List Manager wrote:
> From: "C. Pond"<cpond@xxxxxxxxx>
> Subject: [optacon-l] For anyone familiar with the optacons research and design
> Date: Sat, 12 Apr 2014 17:59:59 -0400
>
> For anyone familiar with the optacons research and design and the 
> psychometric research:
> Asside from the convenience of design of the driver circuitry both in the 
> optatons board and on the display driver chips, are their other reasons why 
> the pins are fired alternately: odd, even?
> Would all pins per tactile image being fired simultaneously more quickly 
> fatigue the finger?
> Are the images from the vibrotactile display more clearly comprehended by 
> using alternately firing pins?
> If the tactile image is best interpreted by firing alternate pins, then what 
> is the best firing order?
Dear Charles,

I am a sensory neuroscientist and use the optacon for psychometric research.

I do not think that technically the pins fire simultaneously except within a 
row. The display is interlaced, so that it is scanned one row at a time from 
top 
to bottom, first activating the odds (row, 1, then row 3, then row 5, etc) and 
then it goes on to activate the evens (row 2, then row 4, etc). This means that 
for instance, row 23 is activated closer in time to row 2 then it is to row 1.

I am sure this is a technical limitation related to transmitting lots of 
information very quickly. The interlacing may notionally produce a "better" 
signal by reducing the lag between updating the top and bottom of the pin array.

As to whether this all matters in practice, that is another question. The whole 
cycle is complete in 4.35ms. These sorts of very small time differences are an 
active area of research in neuroscience, but with no definitive answers at 
present. We can potentially discriminate this time difference under optimal 
conditions, but on the optacon that doesn't seem likely to be a significant 
factor. It almost certainly would not contribute to fatigue.

I would say that if you can achieve the same refresh rate, then the sequence of 
pin firing almost certainly will not matter.

Good luck with your efforts!

Richard Vickery

-- Dr Richard Vickery
Director of Learning & Teaching Operations
School of Medical Sciences,
UNSW Australia
ph. 61 2 93851676, fax 61 2 93851059
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[optacon-l] Re: For anyone familiar with the optacons research and design

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