Circuit that produces a tingling sensation in the fingers.

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Hello all

Without going into the application in too much detail we are looking
into
the possibility of allowing the identification of items through a
persons sense of touch.

So what I am researching at the moment is passing a waveform down a
pair of wires which when held (the wires that is) will allow the
person to identify that they have the correct item (correct pair of
wires in this case).

Is there any information out there on this sort of thing? Has anybody
tried this before? What sort of safety regulations etc. apply?

Any help or suggestions appreciated.

Regards

Denis

Re: Circuit that produces a tingling sensation in the fingers.
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Limit to 5ma (c.f. GFI)

Maybe you wanto have a finger worn device that delivers the
"tingle code" based on RFID?  That could enable a blind
clerk to work at a store someday.

I suggest you look into PWM (pulse width modulation).

Prior electrocutaneous example: http://kaz.med.wisc.edu/research.htm

Re: Circuit that produces a tingling sensation in the fingers.

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I don't know what regulations apply but it seems like this would be
exceptionally dangerous for people with electronic life-suppor
equipment implanted in their bodies. (I'm thinking of pacemakers here.)

Just something to keep in mind. Sorry I don't have any real information.

--Mac


Re: Circuit that produces a tingling sensation in the fingers.
On 4 Dec 2004 08:55:33 -0800, snipped-for-privacy@utvinternet.com (Denis

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To expand on what others have said, the main safety issue is
going to be keeping the current from passing through the
heart (for pacemakers of just those with sensitive hearts),
which basically means somehow guaranteeing that the
current path is all in one hand, never from one hand to
the other, or to an external ground, etc.

One practical problem you will quickly encounter is that
the voltage needed to produce a given current varies
quite widely, since the skin pads of the finger tips are
not very conductive when dry.

Best regards,


Bob Masta
dqatechATdaqartaDOTcom
 
            D A Q A R T A
Data AcQuisition And Real-Time Analysis
           www.daqarta.com

Re: Circuit that produces a tingling sensation in the fingers.
Re: Circuit that produces a tingling sensation in the fingers.
snipped-for-privacy@utvinternet.com (Denis Gleeson) wrote in message
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An easier solution would be to use vibration, a small vibration motor
(the type used in pagers), for instance, attached to the item can give
the same tactile feeling (tingling) without the danger or headaches of
passing currents thru items (and people!).  Whether its practical or
not depends on your specific application.

Re: Circuit that produces a tingling sensation in the fingers.
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Very silly and exceedingly dangerous idea. No lawyer or insurance
company will touch you with a fifty-foot cattle prod.

Modulate the speed of a pager motor held in the hand. You can find
good examples of this kind of technology in the sex toy industry (and
I am not being facetious). See for instance
<http://www.babeland.com/page/TIB/PROD/vibrators-couples/DM215780 . If
the intended users of this appliance can tell the difference between
the various settings, then your intended users will be able to, also.

Re: Circuit that produces a tingling sensation in the fingers.
On 4 Dec 2004 08:55:33 -0800, snipped-for-privacy@utvinternet.com (Denis

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This may not be very practical. The sensitivity level (too little/too
much) is in a rather narrow range and varies greatly between persons.
What one may not feel another goes OUCH. As ohters have stated, use
some kind of vibrating transducer, piezo or micromotor.

- YD.

--
Remove HAT if replying by mail.

Re: Circuit that produces a tingling sensation in the fingers.
Check out the medical device called a "Tens" unit, it's send a small tingle.

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Re: Circuit that produces a tingling sensation in the fingers.

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The first part of the problem is to find a set of nerves on/in the body
which can be used to "see". The fingertips are sensitive, but very small.

I would try the skin on one of my thighs, it is fairly easy to attach a
thin elastic cloth around it and leave it on all day.

Then I need a way to excite the nerves in the skin of my thigh.

200*300 points, or more, on the inside of the cloth will excite the
nerves and create a picture which wraps around my thigh, and I use the
nerves in the skin to "see" it.

The idea about electrostimulation fits well into this device.
I would simply try different combinations of frequencies and currents
until I found a setting which gave the best "image" without being painful
in any way.
Mechanical stimulation is also possible, but would be a little more
difficult to manufacture.

A small videocamera can be hidden below or above my own face, in a
band around my head, like a tennis player's sweatband, for example.

So I would feel with my thigh what the camera sees.

With some training it could become really useful.



--
Roger J.

Re: Circuit that produces a tingling sensation in the fingers.
produces a tingling sensation in the fingers.', on Fri, 10 Dec 2004:
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IIRC, you have picked the body area where nerves in the skin are most
sparse.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
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Re: Circuit that produces a tingling sensation in the fingers.

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That may be so but the number of receptors is big enough.
Touch the thigh anywhere very lightly and you
will feel it and you can tell exactly where it is touching.

I thought about the back of the body first, because it is big area, but
it would need some kind of adhesive and very flexible surface to stay in
contact with every piece of skin. An elastic cloth around the thigh stays
in contact with every piece of skin under it.

To make a prototype I would try to find a very thin and flexible wire,
which I could fix in the cloth, by sewing into the fabric. At the end of
the wire I would take off the isolation for a few millimeters and make a
loop or knot which does not irritate the skin mechanically.
(copper wire may irritate the skin, so I would get some other surface
metal on the wire, or chemically add a layer of zink or whatever works
better against the skin than copper)

Then I need a microprocessor which can be programmed to take the average
of the light level in one small area of the video picture and send a
signal of that level to the skin. Maybe 4*4 pixels for each skin
stimulation point. (Because the number of pixels in the camera will
probably be much higher than the number of pixels in my thigh cloth.)

We need controls for intensity and contrast for the skin. They will work
just like the intensity and contrast control on a tv. I might want to
adjust these controls during the day, and when I sleep I turn down to
black screen, or take of the cloth.



--
Roger J.

Re: Circuit that produces a tingling sensation in the fingers.

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That is a good idea too, and it would simplify the wiring as the camera
and the skin area are so close. The whole device could be integrated in
the head band. But I wonder if it would be better for feeling where
things are in the picture.

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I am not talking about painful levels, just a tingling sensation.
 
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You mean for translation from electrical signals to mechanical?

The beepers in pocket computers are like a piece of tape, thin adhesive
piezoelectric material. It can produce a mechanical movement controlled
by electrical signals. Yes, it could work too.


--
Roger J.

Re: Circuit that produces a tingling sensation in the fingers.

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Seconded.  Keeping in mind that our nerves themselves are operating
based on electricity, I suspect that the basic rule of thumb is:
there's no such thing as safe electrostimulation of sensory nerves.
Your stimulus can either be too weak for anything to be registered at
all, or too strong to be safe.

The margin between these two thresholds on stimulus strength is
probably too small to be safe for everyday usage other than in a
*very* closely controlled environment (say, within shouting distance
of an ICU, with trained medical personnel controlling the apparatus,
given a rather specific medical indication for doing it).

--
Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Re: Circuit that produces a tingling sensation in the fingers.

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Since the late 1970s there were devices available called Optacons.
http://www.nfbae.ca/publications/index.php?id37%5

Unfortunatly this technology has disappeared from the market. It essencially
consists of a neadle array (20 x 5) where such trigger is stimmulated by
vibrating certain sets of these pins at a time.
This in fact allows detailed pattern recognition without the effect of
distress on the finger.
I am using such device for 25 years now myself and as an engineer I am
constantly looking for techniques to replace / rebuilt it.

Applying electricity directly to the finger is imho not a good idea. Apart
from safety considerations and possible long-term electrolytic effects I
would assume that you'll lose sensitivity for this after a while.
Vibrating mechanics of some kind triggered by something like an AC current
would work but in order to provide useful information this requires a
complex mechanical setup - just like on the Optacon.

The most promissing approach that I ever considered is to create haptical
stimulation by electrostatic / magnetic fields similar to what you can
experience if you switch your old model color TV off and touch the tube
glass.
If one would switch such fields on and off quickly, shield the whole thing
by some polymer with a suitable electronegativity characteristic and then
put the finger right on this plastic it may be possible to trigger a certain
part of the finger for a short time and - as a result - produce a picture.
This is what the optacon does but the approach could result in a much less
gragil technology with higher resolution and lower costs.

/Roland



Re: Circuit that produces a tingling sensation in the fingers.
I read in sci.electronics.design that Roland Zitzke
about 'Circuit that produces a tingling sensation in the fingers.', on
Wed, 8 Dec 2004:
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That would be a very distinct advantage. (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
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Re: Circuit that produces a tingling sensation in the fingers.
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Roland, is this a device to help you see? I've read about these, but
never actually had any direct contact. Can you recognize different
faces? Or the fact that a face is in front of you?

--
Regards,
   Robert Monsen

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Re: Circuit that produces a tingling sensation in the fingers.

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Yes, I use it because I am blind and it lets me recognize images when moving
a CCD camera over it.

As mentioned the represented image is quite small (20 x 5) and this is not
enough for recognizing complex structures like a face in the sence that I
could tell two faces apart.
Biometry is a science of it's own ;-)

With a device I suggested it could be a much larger image and that would
certainly enable "TV for the blind" to some degree.

/Roland



Re: Circuit that produces a tingling sensation in the fingers.



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After I have read this post, I have had the idea, that I would be able
to propose a novel idea for this purpose, that may be very attractive,
because this allows to makes devices with even large surfaces, that can
produce even large pictures. This idea is based on may experience, and
this is the reason, whyI think, that this will work, but it requires
some money for the development. The device will not contain any moving
elements.

If somebody is interested in it, I would be able to do this development
and create a product. This can be surely patented.


Wieslaw Bicz

---------=== mailto: snipped-for-privacy@optel.pl  -=-  http://www.optel.pl ====-------


Re: Circuit that produces a tingling sensation in the fingers.

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Yes, I guess it would be possible to apply a core technology similar to
displaying TV pictures line by line.

experience, and
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You are right, and this is probably the problem why such technology is not
further developed or even sold.

The device will not contain any moving
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Sure not, the three things I see as obstacles is
a) To find a suitable surface material
b) to find components which are able to switch a high voltage on and off
with high frequency and deflect it.
c) Do extensive testing to see if the approach as such works as we think it
might word.
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But I simply don't see a big market for such product since even my old
machine is no longer made.
/Roland



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